Zac Efron has stripped down to scale the rocky terrain of New York’s Catskill Mountains as part of an adventure series for NBC with Bear Grylls.

Speaking about Efron’s involvement in the dangerous adventure, 40 year-old Grylls told People magazine “We reached out to him and he kindly said he was a fan of the show and he was in 120 per cent. He asked for the biggest, baddest adventure and it was an honour to oblige”.

Other celebrities scheduled to take part in the excursions of the series are actors Channing Tatum and Ben Stiller.

Running Wild With Bear Grylls premieres on NBC on July 28, but for now, feast your eyes on the trailer, in which Zac announces “This might be the appropriate time to tell you…I can’t swim”.​