Kate Winslet at the Venice Film Festival
09/02/2011 AT 10:15 AM EDT
's film roles have included a doomed Titanic passenger and an SS guard, but her turn as a concerned Brooklyn mother in the Roman Polanski-directed Carnage
was a real stretch – for her stomach.
The Oscar-winner, 35, steals the show in a scene that features her character projectile vomiting during a discussion about a playground scuffle involving her son.
"I had to contain a lot of vomit in my mouth which is not possible for a person to do," Winslet said during a news conference Thursday, before the movie's premiere at the Venice Film Festival. "So without going into too much detail, it was a fairly complex rig and there was some extremely clever CGI involved."
The scene apparently had the cast – which also includes John C. Reilly, Jodie Foster and Cristoph Waltz – and crew in stitches.
Said Winslet: "It was hysterical. … We were all completely beside ourselves with laughter."
And they weren't the only ones giggling.
"My kids came to work for the vomit day," she said, "and I am so thrilled that they were there because they literally have not stopped talking about it since."