Bristol Palin and her 2-year-old son, Tripp, are going to do a reality TV series for Bio channel in which they move in with actor brothers Chris and Kyle Massey and they all live together in the Masseys’ big house in an exclusive Los Angeles neighborhood.

Bio cable network has ordered 10 half-hour episodes of the unnamed reality series in which Bristol — the country’s most famous unwed-pregnant-daughter-of-vice-presidential-candidate-turned-abstinence-advocate-turned-“Dancing With the Stars”-competitor — moves from Alaska and shares a roof with “her good friends Chris and Kyle Massey” while working for a small children’s charity. The name of the charity is still under wraps.

Think “Three’s Company” meets “Three Men and a Baby,” one source said of the new series.

If all goes well, the show will unfold on Bio, but could then be repurposed on A&E and Lifetime; all three networks fall under the A&E Television Networks (AETN) banner — which is mostly owned by ABC parent Disney and the Hearst Corp., though Comcast-NBC Universal owns a smaller stake.

Bristol and Kyle — rapper and star of Disney Channel’s “That’s So Raven” and “Cory in the House” — were both competitors last fall on ABC’s “Dancing With the Stars.” The two were that season’s youngest competitors. Many people presumed both would be eliminated quickly from the competition. Instead, Bristol wound up finishing third, and Kyle second, behind winner Jennifer Grey.

According to a source who has knowledge of the situation, Bristol had planned to return to Los Angeles after her “Dancing” experience, and she and Kyle had been looking for something to do together. Kyle has a relationship with the new show’s production house, Associated Television International; he works on its syndicated clip show called “World’s Funniest Moments,” and the two Massey brothers also have been “roving reporters” on the company’s production of the annual Hollywood Christmas Parade.

So they all got together and brainstormed, and out popped this new series.

Meanwhile, Bio channel was looking for its signature stamp — you know, like A&E has “Gene Simmons Family Jewels” and “Hoarders” and “Intervention” and “Dog the Bounty Hunter” and “Storage Wars.” Bio’s reality series include the lesser-known “Aftermath With William Shatner,” “Celebrity Ghost Stories,” “I Survived . . . ,” and “Paranormal State.”

“Since [‘Dancing’], Bristol, Kyle and Kyle’s brother, actor Christopher Massey, have become best friends,” Bio said in Monday’s announcement.

“So much so that, since Bristol and Tripp have to move to Los Angeles for her new job, she decided to move in with the Massey brothers, who are also about to realize how much their lives are about to change.”

Golly, if only we got a buck every time an announcement for a new reality TV series included the phrase “about to realize how much their lives are about to change.”

(FYI, Chris Massey played Michael Barrett on Nickelodeon’s “Zoey 101.” )

“As Bristol Palin gears up for her work in this charity, she is allowing cameras exclusive access into her personal life for the first time,” Bio gushed, calling Bristol “the most famous single mother in America.”

“Bristol is the kind of personality BIO is drawn to,” Bio’s exec veep of programming, David McKillop, chimed in for Monday’s announcement. “Her personal life has been playing out in the media for several years, but this will be the first time she’s opening up her real life, with her son and her friends the Massey Brothers.”

Bristol Palin is, by now, an old hand at this game. Besides “Dancing With the Stars,” she showed up sometimes on TLC’s “Sarah Palin’s Alaska.” And she reportedly had been in talks to allow cameras exclusive access into her personal life for the first time (as Bio puts it) for a reality TV series a while back, when she and Tripp’s dad, Levi Johnston, briefly got back together and announced their betrothal to the world — and her parents — in Us magazine.

Oh, and in anticipation of your question: It’s not yet clear whether Sarah Palin will pay a visit to the Palin/Massey household during the run of this new Bio show, according to our source. Bio hasn’t gotten back to us yet on that one.

‘Today’ switch official

With the dust settled on the whole Katie Couric/Scott Pelley “CBS Evening News” fracas, NBC News decided the coast was clear to announce that “Today” show’s Meredith Vieira is leaving and Ann Curry will, at long last, get to wear the “Today” co-host tiara.

“It’s a difficult day for me . . . after months of personal reflection and private conversations through my family and my friends, I’ve decided to leave ‘Today’ in June,” Vieira said on Monday’s “Today” show, explaining that she wants to spend more time with her husband and kids but that she is in talks about staying with NBC News in some capacity.

“Even as I say this, and I know it is the right thing, I’m really sad, because for the past — I like to say 10 years, but it’s only been five — this has been my second home,” Vieira continued, while sitting on the couch next to co-host Matt Lauer, along with Curry, “Today’s” Al Roker and Natalie Morales, who is taking Curry’s place as “Today” news reader.

(Not on the couch but also part of Monday’s news, MSNBC’s Savannah Guthrie has been named co-host of “Today’s” third hour, joining Roker and Morales in June.)

“Even as we are sad to say goodbye to Meredith, we are thrilled that Ann Curry will be taking a step from this cushion, leaping over here, and coming over to this cushion,” said Lauer, gesturing to Vieira’s spot.

“I feel like the high school computer nerd who was just asked to the prom by the quarterback of the football team,” Curry gushed, before adding: “But I have to say, I think this day is really Meredith’s.”

“It’s really Ann’s day,” Meredith said, getting in the final word on that debate during a news conference after the show.

Meredith insisted that she’s not leaving because, as some reports said, her husband, who has multiple sclerosis, is in bad health. She said she’s departing because he is now in good health. “I appreciate what that means. . . . I want to be there with him, and I want to have fun and appreciate our time together.” Those reports, she said, “diminished him and diminished me, so I want to set the record straight on that.”

Matt got asked about reports that he might be leaving “Today,” as well, when his long-term contract expires on Dec. 31, 2012 — possibly to join soon-to-be-former CBS evening newscast anchor Katie Couric on a syndicated talk show. Couric announced April 26 that she’s leaving the evening-anchor gig but has yet to announce where she’s going next.

Anyway, Matt’s answer was so riddled with qualifiers that it will do nothing to stanch that rumor. Here are the highlights:

“I have a long-term deal with NBC. I love this job. I love this place. It’s not even worth talking about now. . . . We spoke about the possibility, but I’ve spoken about lots of possibilities over the years. . . . I just determined there wasn’t any need to continue the conversation for now. Katie’s timetable is more accelerated than mine. . . . Yes, we talked about it but, at this time, it’s not even worth talking about.”

“For me, I use the word ‘bittersweet,’ ” Meredith replacement Curry said sadly, when she got her at-bat during the news conference.

“As I said this morning, we just love you,” Curry continued, presumably talking to Meredith (we were listening in on a conference call).

“You brought a graciousness to our broadcast but left this tremendous body of work,” Curry continued. “I don’t like change in the morning — even this change.

“I’m humbled to work with you in this capacity. And, you know I’m telling the truth,” Curry continued, now addressing Matt, and sounding more and more Eve Harrington-like by the minute.

“You are the best. To sit alongside you will be one of the greatest things in my life.”

“It’s not that great,” Matt replied, very Addison DeWitt-ish-ly.

This could turn out to be the best coupling in “Today” show history.

“I’m stunned by the quality of the people we get to work with,” Curry continued, undeterred. “And I’m excited for you, Savannah, to get to join our family and to be here with us. I think you’re going to love this.

“I mean, buckle up, it’s a great ride.”

Abdul joins ‘X Factor’

Fox announced the inevitable: Paula Abdul is joining Simon Cowell on the singing competition “The X Factor” when it debuts this fall.

“This show would never have been the same without Paula,” said Cowell of his show, which has somehow survived without her in Britain, where it originated, and other countries.

“[I] can’t believe I am saying this — I have missed her a lot, and I am thrilled she’s on the show,” Cowell continued.

Abdul’s reunion with Cowell on this show had been forecast so long, there would have been bigger news had a deal not been struck. And yet, the press was all atwitter over the weekend regarding whether she’d show up Sunday for the first day of “X Factor” auditions in Los Angeles, joining Cowell and Cheryl Cole and L.A. Reid as judges. Cowell had already announced Cole and Reid in advance of the show’s opening audition day; the fourth judge was left a “mystery” until she walked out on stage with him at USC’s Galen Center and the audience erupted, according to various media reports.

Cowell and Fox are hoping his reunion with Abdul will put the spotlight back on the new competition series, which recently has very much taken a back seat to a resuscitated “American Idol” these past few months, as well as NBC’s new singing competition, “The Voice,” which stars Christina Aguilera, Cee Lo Green, Adam Levine and Blake Shelton as celebrity mentors/judges.

Cowell and Abdul were teamed with Randy Jackson as judges on “Idol” until Abdul walked right before the start of season nine, when she could not agree with the network and the producers over a new contract. The dancer/choreographer/pop singer was unhappy that she was not being offered the same kind of money that was being offered to Cowell and “Idol” host Ryan Seacrest for their participation.

Since then, Abdul headlined a competition series on CBS, “Live to Dance”; it flamed out in one season.

“I am excited beyond words to be a part of ‘The X Factor,’ ” Abdul said in Fox’s announcement, only she wasn’t: She had lots more to say.