The Irish star is set to play cop Ray Velcoro in the second season of the show, which also features Rachel MCAdams and Vince Vaughn, and he was asked to gain weight to perfect the character's paunch.

He tells Britain's Glamour magazine, "People think it must be fun to eat what you want - and it is, for the first day. Day two, when you're already on your second cheeseburger and fries with a chocolate shake by 11am, not so much."

Images obtained by WENN show Farrell in character filming for the role sporting a thick handlebar moustache and a much heavier frame.

Series two of the show will debut on U.S. network HBO later this year (15).