Zac Efron was intimidated by Michelle Pfeiffer when he first worked with her.
The hunky actor starred alongside the veteran actress in musical 'Hairspray' in 2007 and will soon be seen with her again in romantic comedy 'New Year's Eve', and he admits he was more relaxed around her the second time.
He said: "I had the chance to work with her on 'Hairspray', but I was very young and I was a little bit nervous to work with her, so I tended to say all the wrong things and I was very bashful around her.
"When I found out that she wanted to play this role, I was in 100 per cent, and it was really great."
Zac initially rose to fame on musical TV show 'High School Musical' - which also starred Vanessa Hudgens, who later became his girlfriend - and he admits he has some very "fond memories" of his time on the set of the teen franchise.
He told 'Daybreak' on ITV1: "It's lovely to reflect. I'm very, very grateful for those days - they are some of my fondest memories and I'm still very close with all my friends so we get a good laugh every time we see it come on TV or anything like that."