When you see Meryl Streep and Alec Baldwin strip for their sex (agenarian?) scene in "It's Complicated," you wonder why they were not nominated for SAG awards.

OK, cheap shot, but I'm only following the lead of writer/director Nancy Meyers, who has her plump and ripened stars taking lots of good-natured digs at themselves.

Baldwin does two nude scenes in "It's Complicated," and shows that his recent commercial success has gone straight to his waistline - he looks like the bear that ate him in "The Game."

But he's having a grand time - nobody enjoys Baldwin's late-career success as a comedian more than he does, and he clearly relishes his role in "It's Complicated," playing a variation on his "30 Rock" role - wealthy alpha-male scoundrel.

Baldwin is Jake, a jet-setting lawyer with a new and gorgeous young wife (Lake Bell) who's not much older than the three grown children he raised with Jane (Streep), wife No. 1.

At his son's college graduation, he and his ex end up at the same Manhattan hotel, and Meyers crafts a nice scene of the two wary adversaries slowly letting their guard down as they gradually get drunk and end up in bed.

Baldwin becomes the showcase in these scenes, which throws the movie off-balance for a bit - it's meant to be told from the point of view of Jane (Streep), who's wrestling with confused emotions. She's both thrilled and appalled to be The Other Woman - her friends (Rita Wilson, Mary Kay Place) advise her to enjoy taking revenge on her rival, but Jane herself is guilty and conflicted.

She is just starting to find herself as a single career woman - she owns her own bakery, and there are some funny and knowing scenes of Jane finding the way to Jake's fickle heart is through his much less fickle stomach. And she's just started to date - taking up with the architect (Steve Martin) who's putting an addition on her fancy Santa Barbara, Calif., home. Yes, it's a Nancy Meyers movie, so the romantic comedy is a three-legged stool - a woman splits her time between two handsome men and a gorgeous house.

"It's Complicated" has some of the structure of a classic romantic comedy, but really works better as a farce. The movie has some up-tempo, lowbrow interludes (Streep and Martin get high, Martin has a virtual encounter with Baldwin's groin) that work, and some earnest moments that don't. The movie spends a lot of time on Streep's worried relationship with her children, and all of it is wasted.

"It's Complicated" is also complicated by the fact that Baldwin, without intending to, steals the movie from his co-star.

He has good rapport with Streep, but his chemistry with himself, with his new role as charming devil, is perfect.