In the 2003 film, Will's character Frank gets drunk at a party and wanders into the middle of the road wearing only socks and sneakers, and the Anchorman star recalls how he managed to horrify members of a nearby gym by stripping off in full view of the facility.

He tells U.K. host Graham Norton, "We were shooting on a street where there was a gym with people on treadmills. I was rehearsing in a robe and I said to the assistant producer, 'Should we tell these people what is going to happen?' When 'action' was shouted and I took off the robe there were shrieks and by take three, I cleared the gym they were so grossed out!"

During the chat, Will remembers making a huge mistake on the Anchorman 2 set by turning down Harrison Ford's offer of dinner after the day's shoot.

He says, "He was shooting on the first day of Anchorman 2 and we were all very nervous to be working with him. He was taking his make-up off and he asked if I wanted to go to dinner. I'm normally really vigilant when working about getting early nights so I said, 'No, I'm good. I have something in my trailer.'

"Then he leaves and I realise I'd just turned down Harrison Ford in favour of a Styrofoam box of food provided by catering. I saw him the next day and tried to reciprocate but we worked until three in the morning so the moment was lost."

Talking to the camera, he adds, "It was just an honest mistake and if I could ever make it up to you Harrison..."