Kirstie Alley (Adam Taylor/ABC)

Slowly but surely we’re learning why various celebs really agreed to another grueling 10 weeks of competition on ABC’s “Dancing with the Stars.”

Last time Kirstie Alley competed on “Dancing” in 2011, she was launching her own line of diet food and wanted to be seen slimming down during the dance competition.

Thursday, after the first round of “Dancing” had aired on ABC,

TV Land announced it ordered a presentation for a new comedy called “Giant Baby” – starring Alley. FYI, a presentation is like a pilot – only a lot cheaper.

In the new sitcom, Alley will play a high-maintenance Broadway star who’s in for a shock when her 26-year-old son — the one she gave up for adoption – shows up at her doorstep after his adoptive mother dies. A series pickup on the new project is “cast contingent” TV Land said Thursday – the casting that’s still in question is that of her “son,” described in the news release as “nerdy and schlubby.” Surely this role won’t be hard to fill — Hollywood’s loaded with schlubby guys, who are all the rage these days. You can’t throw a brick in Hollywood without hitting some schlubby guy on his way to an audition or a meeting with his agent. In fact, the hard thing these days is to find a non-schlub to cast in a show.

Anyway, so long as Alley lasts on “DWTS: AS,” she’s a cha-cha-cha-ing advertisement for her new TV Land series. Alley this week got the second lowest score from the show’s three judges, ahead only of Pamela Anderson, who wound up getting the hook after viewer votes were added into the mix. SO she’s got to step up her game.

Before getting the heave-ho on Tuesday’s results show, Anderson had said, fighting tears, that she hoped to survive at least to Week 2 of the “Dancing” competition because she was set to dance a routine that would be a national TV tease for HER next project — starring in a Broadway production.