Zac Efron paid The Ellen DeGeneres Show a visit recently and revealed to the funny lady the scene in his tightie whities is his favorite in his new movie…

Zac and Nicole both star in this weekend’s new flick Paperboy, and the underwear scene with Nicole, he reveals, was totally improvised.

“Before I knew it, music started to turn up around me,” he recalls, “and [Nicole] kind of looked at me and said, “˜You want to dance?’ And they’re still rolling, so I couldn’t really say, “˜Cut!’ And before I knew it, we were improvising an entire dance in the rain.”

Paperboy hits theaters this weekend.