Scarlett Johansson and Jack Antonoff at their high school prom in 2002 at Professional Children’s School.

Jack Antonoff, the indie-rocker beau of “Girls” creator Lena Dunham, had a sweetheart with even more star power during his high-school days: Scarlett Johansson.

The 30-year-old guitarist from the band Fun. had an unforgettable prom night in 2002 — as seen in these pics of him and the future 𝑠e𝑥 symbol canoodling in a limo.

The couple dated for two years while attending the Professional Children’s School on the Upper West Side.

“When we were in high school, Jack was absolutely obsessed with her, and she broke his heart,” a prep-school pal told The Post. “They broke up shortly after graduation . . . She got swept up in the Hollywood scene.”

Lena Dunham and musician Jack Antonoff at HBO’s Golden Globes party in January 2013.

Dunham, 27, says she knows Antonoff’s romantic past and is not jealous.Scarlett Johansson and Jack Antonoff at their high school prom in 2002 at Professional Children’s School.