Actress Tina Fey worked with a dialect coach to perfect her Russian accent for her new film Muppets Most Wanted.

The former 30 Rock star, who plays a Russian government agent in the movie, refused to take her role in the puppet parody lightly and when she started to struggle with her accent, she agreed to work with an expert to perfect her voice.

She explains, "They (producers) brought this wonderful woman named Jill, who is like a real dialect coach, this British woman who works with like Keira Knightley."

And the coach imparted some important advice: "When you go to do it, it's actually really hard, the Russian, and she told me the tip to remember: 'You're supposed to (act like) you have a piece of poop on your lip, that you want to get this piece of poop off your lip, that you hate everything'

"I said, 'Ok'. So I was thinking, 'I have this piece of poop on my lip', and I was trying super hard and I think I did pretty good."