Vanessa Hudgens is "really surprised" at how trendy Sir Michael Caine is.

The singer-and-actress was shocked to hear the 78-year-old star singing a Katy Perry song on the set of her latest movie 'Journey 2: The Mysterious Island' - which stars DWAYNE 'THE ROCK' JOHNSON and Josh Hutcherson - and she was surprised to hear him advising her on the latest technology trends.

She told You magazine: "When they told me about the cast and about the fact that we'd be filming in Hawaii, it was basically a no-brainer.

"Michael Caine was awesome. I was really impressed that he knew what was hip and trendy. He was singing Katy Perry's 'Firework' one day and then telling me about an iPad feature I had to get the next.

"The whole thing was just a great experience - I'd wake up to the sound of the ocean, play on the beach a little and then mosey on down to work. Who wouldn't say yes to that?"

The 23-year-old beauty - who previously starred alongside her then-boyfriend Zac Efron in 'High School Musical' - has started embracing her "inner child" and "having fun" with her acting roles rather than try to fit in with an older mindset.

She added: "I was always extremely passionate about acting, and when you love something that much, you want to do it all the time. But I've noticed a change In Me over the years.

"When I was younger, I played the adult more because I was acting with adults and wanted to fit in. Now I'm embracing my inner child and having fun."