The Lone Ranger star had to be weighed down for the scene, which required him to release his leg from the pull of the cinder block so Cavill could carry him to safety.

However, the Man of Steel hunk failed the task the first time around as he feared he would drown, and he only learned later on why he had struggled to pull his pal to the water's surface.

Cavill explains, "There's this scene where I'm rescuing Armie from underwater and it's about a 25 foot swim down to him and we're both fully dressed. He's way at the bottom of the pool...

"The first time I go down there, I grab Armie and I start swimming up, and I'm thinking, 'There's no way I'm gonna make the surface.' So I'm dragging a 230 pound man, 20 feet back to the top of the pool, and I realise, 'I'm never gonna make it!', so I just bail on Armie. I totally failed him.

"Afterwards, he was like, 'What happened man?' I was like, 'I just couldn't hold my breath.' He's like, 'I'm really sorry, I couldn't get the cinder block off my foot', so not only was I dragging him up, but I had a cinder block to drag all the way up too!"

Luckily, an onset rescue diver was able to swing into action and hand Hammer a breathing regulator so he didn't drown.