The High School Musical star is clearly in awe of the British film legend, who won legions of new fans as Gandalf in the Lord of the Rings and Hobbit franchises. And it seems the feeling is mutual, as Ian, 76, has started following 28-year-old Zac on Twitter.

"Holy $#!% did @IanMCKellen just follow me?" an overjoyed Zac tweeted.

The pair is yet to interact via social media, but fans will no doubt be keeping their eyes peeled for a conversation between the two stars.

While Zac is yet to appear in a film with Ian, he's worked with movie greats including Nicole Kidman in The Paperboy and Robert De Niro in Dirty Grandpa. The star is also lucky enough to have a Hollywood mentor in the form of Leonardo Dicaprio. Leo, 41, became famous very quickly after his romantic role in 1997's Titanic so was able to advise Zac about life in the limelight.

“He’s a cool guy and he is helpful,” Zac previously told MTV News. “I ask him questions every once in a while, and he gives advice to the best of his abilities, but he’s not like a life coach.”

Back in 2009, he also told GQ magazine the most important tip Leo ever gave him: “I thought I was gonna ask him questions. He ended up asking me questions, and in that, he told me a lot. He said, ’There’s one way that you can really f**k this all up. Just do heroin. If you steer clear of that - the other obstacles you’ll be able to navigate.’ And that makes sense, dude.”

Zac went to rehab in early 2013 but has been sober since June of that year (13). He has never specified why he sought treatment, although admitted he'd been drinking "way too much" during an interview with The Hollywood Reporter.