Dame Helen Mirren has confessed she is "hopeless" at voicing animated characters.
The Oscar-winning actress lends her voice to giant centipede Dean Hardscrabble in Monsters University but admitted she was out of her comfort zone - although her high heels helped.
"I'm actually hopeless at voiceovers," the 67-year-old actress insisted.
"I would've loved to have been in the room with Billy (Crystal) and John (Goodman) and watched the masters at work, but at least I had Dan (director Dan Scanlon) helping me."
She added: "It's always great to have a wonderful director. They sort of guide you and allow you to experiment and do different things and eventually the character appears."
Voicing a character meant Helen didn't have to worry about what she looked like for work.
She said: "Oh, it's fabulous! It's great not to have to get up at 5am and sit in hair and make-up forever, and not to be fiddled with all day long. It just drives me mad but you have to be very patient."
But the star did make sure she wore heels every day, to help her get into character.
"What you have on your feet as an actress is incredibly important," she explained. "And I like to have my body present because to put the energy and expressiveness in the voice [alone] is difficult."
Monsters University is a prequel to 2001's animated adventure Monsters Inc and follows Mike Wazowski (Crystal) as he enrols for his first term at college. His plans to become a professional "Scarer" are soon derailed when he crosses paths with Sulley (Goodman) and the formidable Hardscrabble.
The movie is in cinemas now.