When celebrities – cocktail in hand – take the hot seat opposite Watch What Happens Live's Andy Cohen, they spill secrets like never before. Take Oprah Winfrey admitting to smoking weed or Cameron Diaz confessing she "swam in the lady pond." The Real Housewives franchise counts A-listers Lady Gaga, Chrissy Teigen and Anna Kendrick among its devoted viewers. But Jennifer Lawrence has proven to be the biggest Real Housewives of Beverly Hills and Vanderpump Rules superfan, and on Monday night, she took a break from her Joy press tour to play "Plead the Fifth" with Cohen – with PEOPLE on set.
"I love it when people are as enthusiastic about being here as we are about them being here, so it was perfect," Cohen told PEOPLE afterward. "I thought she was candid from top to bottom. I felt comfortable enough asking her about Chris Martin and everything else. I feel like she was a total open book, and I love it when guests come to play and when they're willing to talk about anything."
Mazel, J. Law! Here are the highlights from her WWHL debut:
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Pumptinis with JaxLawrence, 25, began the show with a glass of beer, but Cohen, 47, noted that she's raved about the fruity, pink Pumptinis at Lisa Vanderpump's West Hollywood hotspot ... so he brought out bartender/reality star Jax Taylor to whip one up. (Check out the recipe here.)
"Is there even alcohol in this?" Lawrence asked of the deceptively sweet drink.
Also on the bar? An ice sculpture of Taylor's "original nose," which Lawrence pointed out looked more like a phallic symbol.
"Jax was a surprise to her," Cohen told PEOPLE. "He's a great sport, and look, he had Jennifer Lawrence giving him crap for half an hour. It's pretty hilarious."
Secret Smooch with Liam HemsworthSorry, Team Peeta: Lawrence copped to kissing her hunky Hunger Games costar off camera.
"Liam and I grew up together. Liam's real hot," she said, laughing. "What would you have done?"
"I would say yes," Cohen said. "I mean, I pick Gale over Peeta any day."
"I did, at one point!" she said, earning a high-five.
During the commercial break, she joked, "I gotta call Liam!"
(Kind of) Confirming Chris MartinLawrence and Coldplay rocker Chris Martin, 38, were first linked in August 2014 and ended their on-off relationship for good a year later.
"You and Chris Martin never really confirmed whether you were together or not?" Cohen asked coyly.
"We never did," Lawrence said.
"Were you?" he prodded.
"Come on!" she said, laughing.
Pre-Oscars PotSusan Sarandon once told Cohen she's been stoned at every major Tinseltown event except for the Oscars. For Lawrence, the "reverse" is true.
"I smoked pot at none of them, but I saw my brother smoking out of a bong before one of the Oscars, won't say which," she explained.
"Did you take a little hit?" Cohen asked.
"Um, yeah," she replied, sipping her Pumptini.
"Was it when you won?" Cohen said.
"I plead the fifth," Lawrence said.
Making Peace with Melissa RiversIn Joy, Melissa Rivers makes a cameo as her late mother Joan Rivers. But the legendary comic and Lawrence clashed in the past: The Silver Linings Playbook star criticized Fashion Police for fat-shaming celebrities, and Joan fired back on Twitter, declaring Lawrence "a hypocrite."
When a WWHL caller asked Lawrence if filming with Melissa was awkward, she said there were no hard feelings.
"I really do love Joan Rivers, she had such an incredible life and is an unbelievable woman. I just am very opinionated, too," she explained. "I don't think we would have had a beef had we met, so I said that to [Melissa] and complimented her mom and kind of got it out of the way immediately. She's so nice and great, so I got it out of the way and then we were great."
Battle of the BFFsEver since Lawrence and Amy Schumer were spotted splashing around on a jet ski last summer, they've embodied #SquadGoals, from dancing shoeless on Billy Joel's piano to writing a movie together. Just don't call the Trainwreck comedian Lawrence's best friend.
During the aftershow on BravoTV.com, a caller named Laura phoned in a question from the airport – and Lawrence burst into giggles when she realized it was her real-life bestie and fellow Pump Rules scholar.
"I just want to clear this up once and for all. Who’s your best friend, me or Amy Schumer?" Laura asked.
"You, sausage!" Lawrence cooed. "You’re my sausage, nobody else could ever – wait, that sounds wrong."
After dishing out some searing analysis of Taylor and his fellow SUR staffers ("What's wrong with you? Do you really lie that much?"), Laura earned an invitation to stop by WWHL herself and bartend.
Watch What Happens Live returns Jan. 3 at 10:30 p.m. ET on Bravo with guests Bob Harper and Cynthia Bailey.