Dame Helen Mirren struggles with voiceovers.

The veteran actress voices a character in forthcoming animated movie 'Legend of the Guardians' and admits she struggled with it far more than she expected.

She said: "It's hard. I really admire the people who are very good at it. Americans are very good at animating voices. I don't know why. They have a freedom with them that we British actors find more difficult to get to. I try to do it as best I can. I'm playing the wicked, evil one. Of course, I'm British, what else?"

Despite her struggles, Helen, 64, is looking forward to seeing the finished movie because she has "no idea" what it will be like.

She added in an interview with Collider.com: "When you do a voice in an animated film, you don't see the finished product at all. You're not animating. You're not doing the voice on the finished product. You're doing the voice long before. In fact, they animate to your voice so you don't see it at all. I have no idea. That's going to be a surprise for me."