Katy Perry's mother thinks she sounds like a bird when she sings.

Mary Hudson is so convinced the 'I Kissed A Girl' singer sounds like a winged creature when performing she has a special nickname for her.

Katy wrote on social networking website Twitter: "night tweethearts! My mom has called me that my whole life, "tweetheart" (since I used 2 sing myself 2 sleep like a bird) but now it's cool! (sic)."

Katy's family nickname was not the only thing the 24-year-old star revealed on the website.

She also let her fans know she has watched new movie 'The Time Traveller's Wife' - in which Rachel McAdams stars as Clare Abshire, an artist who falls in love with Eric Bana's character, time traveller Henry DeTamble - before giving some thoughts on the love lives of Hollywood stars.

Referring to Rachel's relationship with her 'The Notebook' co-star Ryan Gosling, which ended in 2007, Katy wrote: "just finished watching "The Time Travellers Wife," I didn't ball lik I thought I would... maybe it was 2 mushy, maybe I'm soul-less!

"Nah! I just like the Rachel McAdams, Ryan Gosling pair better... PLEASE GET BACK TOGETHER.

"speaking of getting back together, I wish brit & J T were still 2gether wearing that matching denim outfit they wore to VMA's one year.EPIC (sic)."