Some kind of wonderful! In a sweet moment, Danica McKellar admitted that her very first kiss happened while the cameras were rolling. 

The former child star, now 39, opened up about her lip-lock in a new commentary video that accompanies the DVD set of the complete The Wonder Years series. McKellar began appearing as Winnie Cooper on the beloved family sitcom when she was just 13 years old. 

In the January 1988 premiere episode, Winnie has her first kiss with Kevin Arnold (played by Fred Savage), and the smooch served as McKellar's first kiss as well. 

In the scene, Kevin is comforting Winnie after the death of her brother, holding her and putting his jacket around her shoulders. The youngsters then stare into each other's eyes and kiss as Percy Sledge's "When a Man Loves a Woman" swells in the background. 

"It was really my first kiss," McKellar spilled in the series commentary. "I remember reading the script and seeing that I was gonna have a kiss, and I was like, 'Oh my gosh! I'm about to have my first kiss!'"

"I was totally nervous," the actress continued. "On set, it was really nerve-wracking because there's 50 people standing around watching you. The one upside to having your first kiss on camera is that you know for sure it's gonna happen. You don't have to wonder! The downside is that you have an audience. That was crazy."

The kiss that aired on ABC, however, was not McKellar's true first kiss. 

"I remember sitting there on that rock, going, 'Oh my gosh, I'm about to have my first kiss. It's about to happen! It's about to happen! It's about to happen!'" McKellar explained. "Now, in the story, my brother's just died, so I'm supposed to be really sad. But I got so excited that I got this smile on my face. Of course they couldn't use the first take. The one that you see is take number six."

Watch McKellar and Savage chat about their first (and sixth!) kiss in the video above!