Sideshow: Shia and Megan: Costars coupled

Shia LaBeouf and Megan Fox engaged in sexual relations while filming the first Transformers movie, the manchild admits to Details.

"Look, you're on the set for six months, with someone who's rooting to be attracted to you, and you're rooting to be attracted to them," said Shia, 25, who is promoting Transformers: Dark of the Moon.

"I never understood the separation of work and life in that situation. But the time I spent with Megan was our own thing, and I think you can see the chemistry onscreen."

Things got sticky when Shia was asked if he hooked up with Megan when she was dating now-husband Brian Austin Green.

"I don't know, man. I don't know," he said, repeating the phrase 12 times in various intonations. "It was what it was," he finally said.

An American wedding

Who would want to wed on a Monday? America Ferrera would.

The 27-year-old Ugly Betty star and beau Ryan Piers Williams tied the knot Monday night, her rep tells People, in "an intimate setting amongst close friends and family," including Vanessa Williams, Rebecca Romijn, Jerry O'Connell, and Blake Lively. "The bride wore a dress by Amsale's Christos label and Fred Leighton earrings."

My teacher, Conan

Friends alum Lisa Kudrow tells More mag that when she was a wannabe, she really struggled in her improv acting class. Until she met (and briefly dated) classmate Conan O'Brien.

"He was really smart, really funny, and he thought I was funny," she says. He encouraged her to stick to acting. But their romance fizzled: "We were better as friends."

Lady Gaga defrauds charity?

An attorney named Alyson Oliver has filed a lawsuit in Detroit, claiming Lady Gaga lies when she says all proceeds from sales of her "We Pray for Japan" wristbands benefit Japanese tsunami-relief efforts. The suit, which seeks class-action status, claims Gaga's website adds an inflated shipping charge atop the item's $5 price, which Gaga may be pocketing. Her Gagaship's rep says the suit is "misguided . . . and without merit."

Emma Stone, proud dropout

Emma Stone tells Vanity Fair she doesn't regret her decision to drop out of high school. Anyway, she got to graduate on screen.

"I did Superbad in what would've been my senior year," she says. "I was playing a senior, and had I graduated I would've missed that opportunity, and had I missed that opportunity I wouldn't be here right now."

A kiss for America

The world's most famous male tongue, Gene Simmons, reveals more of his serious side, telling Parade.com why America has been so important to his family.

"I'm an immigrant from Israel and my mother is a concentration camp survivor from Nazi Germany, and America in a very real way saved my mother and my people," the 61-year-old KISS rocker says.

Gene, who claims to have slept with more than 4,600 women (a current estimate puts it at 4,897), admits he and longtime gf Shannon Tweed may be on the verge of breaking up.

"Men are not reflective," Gene says. "We're in the here and the now. Women are wiser. . . . They see the bigger picture."

Hefner is OK. Thank heavens!

Speaking of self-satisfied womanizers, Hugh Hefner seems to be recovering quite nicely from his dumpage at the hands of Crystal Harris. Hef, 85, last week said he had a new "best girl," Anna Sophia Berglund.

Seems he's played some musical chairs again: Now Hef says Anna's just a pal. His real gf is Canadian model Shera Bechard, 27, who'll be Playboy's Miss November.

The light of their life arrives

Tia Mowry, 32, of BET's The Game, and hub Cory Hardrict on Tuesday welcomed their first baby, a yet-to-be-titled boy. Mowry, who starred as a teen with twin sis Tamara in the sitcom Sister Sister, told Us earlier this year that Cory was super-supportive during her pregnancy: "He cooks for me every day." The duo wed in April '08.

Tidbits 'n' pieces

Beloved Smurf lust-object Smurfette models "the hottest shoes, handbags, hats, and jewelry" in Harper's Bazaar's August issue, the mag says. The sexpot's (smurfpot's?) movie The Smurfs opens July 29. . . . Johnny Depp performed with Alice Cooper on Alice's anthems "School's Out" and "I'm Eighteen" in a surprise appearance at Alice's gig Sunday in London.

Existentialist quote du jour

Howie Kohlenberg, 47, who appeared on the debut episode of Jerry Seinfeld's show Marriage Ref, tells the New York Post the show destroyed his 14-year marriage.

How does Seinfeld feel about Howie's troubles?

"I love it, I love, I love it!" he tells the New York Daily News.

"When people get upset I enjoy it. That he's having problems, and blaming me . . . anything that alleviates the withering, blithering boredom of existence, I'm in favor of."

VF rep: No LiLo in VF!

A Vanity Fair rep on Tuesday denied a New York Post report (which also appeared in "SideShow") that Lindsay Lohan is the mag's September cover girl.

What's Palin's decision?

Will Sarah Palin enter the 2012 presidential race? She's already made a decision, her lil' girl Bristol Palin told Fox & Friends Tuesday.

"We've talked about it before," says Bristol. "Some things just need to stay in the family."