The Ocean's Eleven star made a cameo appearance in the hit programme in December (14) as part of a skit for British charity telethon Text Santa, but he insists he would never return to the role.

Clooney referred to his critically-panned 1997 movie Batman & Robin, which he claims nearly destroyed the superhero franchise, and joked that Downton Abbey star Hugh Bonneville has banned him from the set.

He tells U.K. chat show Good Morning Britain, "I've been thinking about (Downton Abbey) a lot and I think since I nearly destroyed the Batman franchise, I could hurt that series really badly if I came back, so I think.. They've asked me not to come back... Hugh called me... And the truth was I did a three-parter and they cut me completely out. So Hugh called me and said sorry we did that... Don't even come to the neighbourhood."