How does Superman pee in that suit?!

Los Angeles - Henry Cavill got a zip stitched into his Superman costume so he could use the toilet.

The 32-year-old star wasn't taking any chances when filming Batman v Superman: Dawn of Justice and arranged for alterations to be made to the crotch of the skin-tight suit because of the "enormous discomfort" he felt when needing to urinate during shooting for Man of Steel in 2013.

Asked whether it was his idea to get the zip during an interview on This Morning, he said: "Yes, absolutely. After doing Man of Steel I was done with the enormous discomfort of not being able to use the lavatory whenever I so chose and so I made sure they put one in this one."

Superman also disguises himself as Clark Kent by wearing a simple pair of glasses and office work attire.

But Henry and his pal weren't sure whether the method of camouflage would actually work in real life so they put the idea to the test in the busy tourist district of Time Square, New York, recently.

The actor recalled: "My friend and I were discussing the lack of validity of the glasses and some people say it's not a great disguise ... so we went to go to put that to the test, and we went to Times Square, and I wore a Superman T-shirt, not even the glasses, and a coat on, and stood underneath the Batman V Superman poster, which is a huge big thing wrapped around the building.

"And we got stopped twice, once by someone to ask directions, and another time because someone was in a coffee shop (behind us) and they said, 'Can you please stop taking photos'."

Watch the trailer here:

Batman v Superman: Dawn of Justice opens in cinemas nationwide on Thursday, 24 March. 

(Photos: Warner Bros.)