As a general rule, it’s never a great idea for a D-list celebrity to slink back into the limelight via a reality show years after their 15 minutes of fame. So the odds weren’t great for photographer Larry Birkhead, best known as the father of Anna Nicole Smith’s daughter — the guy who won the complicated suit claiming paternity after the Playboy model died — when it was announced he would appear on the season premiere of Bravo’s “Millionaire Matchmaker.”

Still, this was also intriguing news, because Birkhead has surprisingly stayed out of the spotlight living in his home state of Kentucky for the past eight years since Smith’s death; save for a few questionable red carpet appearances with their adorable daughter, Dannielynn.

As it turns out, Birkhead’s oddly charming appearance on Sunday’s “Millionaire Matchmaker” was a rare example of reality TV’s plus side: Sometimes, it pays to show your true personality to millions of strangers, especially when people might have misconceptions about you.

Those who knew Birkhead’s name were likely only familiar with him from the highly-publicized battle over Smith’s baby daughter after she unexpectedly passed away in February 2007. Multiple men claimed to be the father, and when a DNA test proved it was Birkhead’s baby, he gloated outside the courthouse with his hands held high: “I hate to be the one who told you this, but. . . I told you so!” he announced to the crowd. (Birkhead later told Oprah that looking back, he’s pretty embarrassed by that reaction; he was just swept up in the emotion.)

Anyway, Birkhead, 38, apparently hasn’t really dated since Smith died, so that’s where “Millionaire Matchmaker” Patti Stanger came in. (In case you’re wondering about the connection, Stanger once appeared on “The Anna Nicole Show” on E!, Bravo’s cable cousin, and this season she’s matching up celebrities.) During the hour-long episode, Birkhead came across as a genuinely nice guy single dad who is completely clueless about dating.

“I’m a little nervous about doing this dating thing,” Birkhead confessed to the camera. “Because I’m kind of a shy guy.”

Stanger diagnosed part of his problem: He hasn’t moved on from Smith. His house (an enormous mansion in Louisville) is basically a shrine to Smith’s memory. Birkhead admitted it’s a tough balancing act, as he splits his time between his photography business and dealing with Smith’s estate and merchandise involved with her image.

“I try my best to keep Anna Nicole’s memory alive for Dannielynn so I’ll have things throughout the house,” Birkhead said as the cameras showed various dresses and pictures of the model from her younger days. “It’s been hard trying to find that balance of what’s enough for Dannielynn to know her mom — but what’s also the limit to where I can move on and put myself back out there and try to find love again.”

“I’m worried that Larry lives in the past, but that’s what I’m here for,” Stanger confidently told the cameras. She was similarly shocked when Birkhead told her that the single ladies of Louisville don’t pay much attention to him. “Why aren’t they hitting on you?!” Stanger exclaimed.

“I don’t think I’m putting out the ‘hey babe’ vibe,” Birkhead muttered, turning three shades of red as Stanger raved about his good looks.

Frankly, it was just plain fascinating as Birkhead described his life post-fame. He said he made the conscious decision to stay mostly behind the scenes — so much so that he seems to have lost all social skills. After a long sequence where Stanger tried to teach Birkhead how to hit on a woman at a bar (she’s not impressed by his pick-up lines), she eventually set him up with a sweet single mom named Michelle.

Naturally, their blind date was extremely awkward. But in an adorable way, down to a highly uncomfortable “Lady and the Tramp” spaghetti kiss.

At the end of the episode, we got the update that the couple still talks, and Birkhead made plans to go see her in L.A., where she lives. “Larry has broken his shy guy habit,” the show assured us.

Again, a not very consequential hour of TV, but one that showed that Birkhead appears to be a kind, normal guy — certainly not what you would assume from the tabloid coverage years ago. And it serves a nice reminder that sometimes, people can actually benefit from the reality TV world.