Zac Efron: really enjoys swimming in tiger shark-invested waters

With filming currently taking place for their next project in Hawaii, it seems that the comradeship of actors Zac Efron and Adam Devine has officially graduated to a full-blown bromance.

Not content with spending all day together on the set of Mike And Dave Need Wedding Dates, Zac, 27, and the 31-year-old Pitch Perfect star even opted to hang-out during their down-time on the tropical island.

This week, the pair decided that swimming with tiger sharks – the species which is responsible for more fatal attacks than any other – would be right up their street.

Zac, who reckons the tiger shark is his 'spirit animal', posted on Twitter a three-and-a-half minute long video clip of their underwater experiences, something which then generated more than 2,000 retweets.

Eating sardines + riding tiger sharks + @adamdevine = Lifetime memories #savethesharks @oceanramsey @oneoceandiving https://t.co/vHhJRHe9C9

— Zac Efron (@ZacEfron) June 16, 2015

The High School Musical star said he hoped his efforts would help raise awareness of the shark's endangered plight.

Still, elements of the clip have proved controversial – namely Mr Efron's decision to grab hold of one of the animals (the incident occurs at around the 2:18 mark).

While speaking to TMZ, one expert, Jeff Kurr, even warned that the dive itself was reckless. He explained that tiger sharks are extremely dangerous and unpredictable – and that grabbing a fin is an aggressive invite to a deadly attack.

Earlier in the week, Zac turned heads in a blue unitard costume while on set.