Lily Collins has recalled ruining the fairytale illusion for a young fan recently.

The 23-year-old actress portrays Snow White in Mirror Mirror, which also stars Julia Roberts, Sean Bean and Armie Hammer.

Lily made a light-hearted joke when she had to gently let a little fan down about the reality of her fantasy film role.

"A little girl came up to me the other day outside my gym with tears in her eyes. She said, Snow White, where are your dwarves? Why aren't you wearing a ball gown?'" she recalled to the Chicago Sun Times.

"I said, Sweetie, Snow White is in her sweat pants today because Snow is going to the gym. Snow needs to do her cardio.'"

In the picture, Julia Roberts stars as Queen Clementianna. Lily wanted to portray Snow White as a more tough character, as she becomes embroiled in a rivalry with the evil queen.

"I wanted her to be more real for young girls. This Snow White will get in the middle of a fight," she explained.

"She also has her own issues. She needs to find her own confidence."

Lily is the daughter of famed musician Phil Collins. The stunning star says her father was eager to give her some sound advice before embarking on a film career.

"My dad says, As long as you're happy and do what you're passionate about and do it for the right reasons, then you've succeeded,'" she smiled.