Maybe it was the “L” on her sweater.

“Watson” star Morris Chestnut confessed on Monday’s “Watch What Happens Live” that his first celebrity crush was Penny Marshall when she was playing sassy single Laverne DeFazio on the 1976-83 sitcom “Laverne & Shirley.” (Watch the video below.)

The revelation literally dropped the jaw of host Andy Cohen.

Chestnut explained that “she was kissing guys and stuff,” prompting Cohen to comment: “Laverne was, as they would say at the time, easy. You felt like you had a green light.”

“Maybe that’s what it was,” Chestnut replied.

The camera eventually panned to fellow guest Jon Hamm, who raised his eyebrows in surprise.

Cohen wasn’t about to let go of Chestnut’s admission during the “Pillow Talk” segment. After the “Best Man” actor said “luck” and “respect” were the secret to his longtime marriage to wife Pam, Cohen quipped, “with a little Laverne DeFazio role play.”

Before moving on to direct movie hits such as “A League of Their Own” and “Big,” the late Marshall was nominated multiple times for a Golden Globe for her portrayal of Laverne. Her chant of “schlemiel, schlimazel” with co-star Cindy Williams in the show’s intro became etched in pop culture. She also famously called fooling around “vo-dee-o-dodo.”

Perhaps that’s what caught the young Chestnut’s attention.