In Gladiator II, Mescal plays the grandson of the emperor of Rome, played by Richard Harris in the first film.
Mescal’s character Lucius is forced into slavery following an invasion by Roman soldiers, and must fight in the Colosseum as a gladiator to restore Rome’s glory.
Asked how he got into shape for the role, Mescal said: “I ate a lot of chicken and lifted heavy things.
“I was working with a trainer who circled me like a shark… He went to town, and I saw him every day. It was fun.”
Another of Norton’s guests, Eddie Redmayne, also discussed his physical training for The Day of the Jackal, joking: “I profoundly disagree with Paul – it was not fun, it was horrendous.”
The original Gladiator made $465m (£358m) globally and won five Oscars, including best picture and best actor for Russell Crowe.
Mescal’s interview on The Graham Norton Show will be broadcast on Friday at 22:40 on BBC One and iPlayer.