If Kate Winslet was able to master a Delco accent for “Mare of Easttown,” she has every right to tease Robert Downey Jr. for an accent he did during an audition for “The Holiday.”

Last week, Winslet visited “The Tonight Show” to promote her new HBO series, “The Regime,” and ended up talking with host Jimmy Fallon about the time he auditioned for Nancy Meyers’ beloved 2006 rom-com.

Winslet starred in the film alongside Cameron Diaz, Jude Law and Jack Black.

Fallon recalled auditioning for the role Black eventually received (Winslet’s love interest), which prompted Winslet to go off on how badly Downey performed a certain accent for his audition as her character’s brother (the role ended up going to Law).

“Robert Downey did an English accent, but I thought he was doing Australian,” Winslet said. “And I thought, ‘That’s bad, that’s not going to work, and who’s going to tell him that that sounds dreadful?’”

Fallon tried to bail Downey out of Winslet’s ribbing.

“I think it was an Australian accent, and I think it sounded great,” Fallon said. “But I don’t think the character was supposed to be Australian.”

“It wasn’t actually that great,” Winslet replied. “But that’s really sweet of you to have said that.”

Although Winslet was pretty blunt about Downey’s audition, it’s clear that he’s had a successful run since then. A couple years after the tryout, Downey snagged the leading role in 2008’s “Iron Man,” which revolutionized comic book movies and turned the Marvel Cinematic Universe into the powerhouse it is today.

Plus, he also scored his third Oscar nomination in January for his role in 2023’s “Oppenheimer,” in which he plays Lewis Strauss. He’s already won awards from this year’s Critics Choice, Golden Globe and SAG ceremonies for the role.

“What a hoot,” Winslet said of Downey’s career trajectory to Fallon. “Here he is, winning everything. My goodness.”