Karl goes rock climbing with Hollywood hunk, Jared Leto

Not only is Jared Leto is an Oscar-winning actor and world-touring rock star, but he is also known as a pretty big daredevil.

So while the star was in Melbourne for the Australian leg of his 30 Seconds to Mars world tour, Karl Stefanovic thought he'd challenge him to a rock climbing race.

Jared is a couple of years older than Karl, but he is a big fan of rock climbing so the Today host had no chance once he was strapped in.

READ MORE: Foo Fighters frontman's bombshell cheating admission

"Climbing, for me, is a way to kind of get away from it all, put down the phone, put down your stresses in life and just to be in the moment," Jared said.

"Of course, running around on stage with 30 Seconds to Mars is like the best boot camp for anything athletic, because it's a pretty energetic show - I'm running around like a maniac."

Both are familiar faces on screen, but the pair have more in common than viewers may realise, with Karl also dabbling in the music scene with his recent collaboration with Keli Holiday, one-half of Aussie dance duo Peking Duk.

"Since we last spoke, I launched my own music video and I'd really be honoured if you could have a little look," Karl said.

READ MORE: Karl heats things up in steamy new music video

"You know how to shake it man, look at that... wow!" Jared said with a smile.

And with that, the pair were ready for their climb.

Jared flew up to the top, barely breaking a sweat, while Karl got a bit of vertigo a dizzying two metres from the ground.

So Jared zipped back down and the pair made the ascent together.

"Stop playing games brother, this is your time to shine," he told Karl.

See how Karl went with his climbing efforts in the video above