United Kingdom, April 15 -- Austin Nichols admits he felt "weird" kissing Mary-Kate Olsen in 'Holiday in the Sun' because he was "too old" compared to her.

The 44-year-old actor was "18 or 19, or maybe even 20" when he played Griffen Grayson, the love interest of Mary-Kate's alter ego Madison Stewart, who was 15 when the family romance film was made.

And, because of the age gap, Austin felt uncomfortable when he had to give Mary-Kate, 38, a smooch in Steve Purcell's 2001 flick.

Speaking on the 'Drama Queens' podcast, he admitted: "I was definitely nervous because Mary-Kate was 15, and I was, I think, 18 or 19, or maybe even 20.

"I don't remember, but I was too old. And it felt weird, and it felt wrong.

"And I looked very young, so wa...