Jennifer Lawrence and Amy Schumer let their doofus flags fly while dancing on Billy Joel's piano

Jennifer Lawrence and Amy Schumer are definitely in the honeymoon phase of their BFF-ness: On Thursday, they danced on Billy Joel's piano while he sang "Uptown Girl."

At Wrigley Field.


The two shrinking violets overcame their trademark shyness (We kid! We kid!) and put on a show for the stadium-size crowd, shaking it to a tune that was featured prominently in Schumer's recent comedy, "Trainwreck."

On Friday, the comic posted a video snippet of their antics on Instagram — just like she did back in July, when she made tons of people jealous showing herself, a bunch of her high school friends and Lawrence having more fun than everyone else in the world on a Hamptons vacation involving Jet-Skiing and human pyramid-ing.

"I was like, 'Oh, we're going on a boat tomorrow. You should come.' It was kind of a hypothetical," Schumer told Jon Stewart, explaining how they wound up together on that trip. "And she was like, 'I think I'm coming.' And I was like, 'Oh my God!' "

A couple of days ago, Lawrence told the New York Times that she and Schumer were working on a screenplay together and intended to costar in it as sisters, and gave a heads-up that she was on her way to Chicago for a visit with her writing partner.

"I emailed her after I saw 'Trainwreck' and said, 'I don't know where to get started. I guess I should just say it: I'm in love with you,' " the "Hunger Games" star told the paper, explaining how they connected. "We started emailing, and then emailing turned to texting."

Next thing ya know, you're partying on Billy Joel's piano.

Follow Christie D'Zurilla on Twitter @theCDZ and Google+. Follow the Ministry of Gossip on Twitter @LATcelebs.