Taylor Lautner Can't Stop Giggling While Co-Stars Lea Michele, John Stamos Grill Him on Taylor Swift

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Taylor Lautner may never live down his "Back to December" romance with Taylor Swift.

The 24-year-old actor was hilariously put on the spot by his Scream Queens co-stars, Lea Michele and John Stamos, during a Facebook Live broadcast on Monday, when they grilled him about Swift's heart-tugging 2010 hit.

It's Stamos that brought up the topic first, mentioning an interview he did with ET earlier that day. "I exposed who Taylor dated earlier in one of the interviews," Stamos confessed, leaving Michele to run with it and Lautner to try -- and adorably fail -- to deflect. 

WATCH: Fun Fact! Taylor Lautner Had a Six-Pack When He Was Only 7 Years Old 

"You dated Taylor Swift! I remember that," Michele said. "Should we talk about it?"

"That's hilarious. No! I don't know why you guys want to talk about that," Lautner responded. He did confirm that Swift wrote a song about him, saying "That's what she does," and eventually seemed to confirm the widely-circulated theory that he was the one to inspire "Back to December."

"I think it was one about a sweater and a hat, right?" Michele asked, grasping for the lyrics. "Fans, people, help me! There's something about a hat, right? ... Hat in December!"

(Nope, no mention of a "hat" in that one.)

After falling victim to a serious case of the giggles, Lautner finally conceded: "It's called 'Back to December.'"

WATCH: John Stamos Jokes About Being 'Eye Candy' on 'Scream Queens' Season 2 - 'I Felt Like a Piece of Meat!' 

The former Twilight star dated Swift briefly in 2009 while co-starring in Garry Marshall's Valentine's Day.

"It was a good time," a blushing Lautner told ET's Leanne Aguilera at the FOX Summer TCA Press Tour on Monday. "It was a fun few months there."

Lautner and Stamos also opened up about joining the hit Fox horror comedy in its second season, and Lautner revealed that he actually talked his way out of being shirtless on screen.

"The first script had both of us shirtless in separate scenes," Stamos explained. "He talked his way out of it. It got rewritten."

"I've had so much shirtless in my life that I need a little break," Lautner said, eluding to his frequent appearances sans shirt as Twilight's Jacob Black. "But there is a fair amount of sexy scenes for everyone. I haven't been shirtless yet but I've been stripped down a little bit."

As for Stamos, his shirtless scenes were re-written as well, but with the opposite result.

"Mine went from shirtless to completely naked in the shower," Stamos revealed.

See more from the hilarious interview below.

WATCH: Taylor Lautner Opens Up About Keeping His Shirt on for 'Scream Queens'