Lena Dunham jokes about finding a photo of her boyfriend, fun. guitarist Jack Antonoff, with his ex Scarlett Johansson Credit: Michael Kovac/Getty Images for Moet & Chandon

Wait, is that ScarJo? During an interview with Grantland's Bill Simmons, Lena Dunham shared a hilarious story from when she stumbled upon a photo of boyfriend Jack Antonoff with his former girlfriend -- Scarlett Johansson.

"The craziest thing that ever happen to me, was like, Old Loves is my passion, I check it like once a week," the Girls creator, 27, said to Simmons in an interview posted Thursday. "And I was going through it and I saw my boyfriend and his girlfriend from high school." After noting the ex to be none other than the Avengers actress, she added: "I know I shouldn't spill that in a public forum, but you can Google it."

Old Loves is a Tumblr page devoted to photos of celebrity couples who are no longer together. The fun. guitarist dated Johansson, 29, for a year back in 2001 when the pair attended the Professional Children's School in New York City.

"She's beautiful, he's beautiful, but it was just so surreal to be looking through this blog that gives me so much pleasure and then there's my boyfriend," Dunham continued. "And I was like, 'My mind is going to explode.'"

Us exclusively confirmed in September 2012 that Dunham and the 29-year-old musician were an item. Johansson tied the knot with actor Ryan Reynolds in 2008, but divorced in 2010. Last September, it was confirmed that the Her star is engaged to French journalist Romain Dauriac.