Katy Perry took her grandmother to 'The Smurfs 2' premiere on Sunday (28.07.13).

The 28-year-old singer was accompanied by her grandma Ann Hudson, 92, on the special blue carpet at the event in Los Angeles and cheeky Ann wore a T-shirt emblazoned with the message ''I've got the hots for Papa Smurf''.

When asked if she chose the outfit for her grandmother, Katy told E! Online: ''You know, if she requests it, with all of her incredible requests.''

The pair have a close relationship and Ann jokingly told her granddaughter to ''drop dead''.

Katy added: ''Grandma and I, it's always been a love-hate relationship. Just always at [each others'] neck.''

This isn't the first time Katy has taken her granny to a showbiz event - the pair previously wore matching Armani Privé gowns at the Grammy Awards in 2011.

Katy collaborated with Britney Spears on 'Smurfs 2' song 'Ooh La La!', which was written by Bonnie McKee who has worked with the 'Firework' hitmaker on numerous occasions, and it will be played over the end credits in the movie.

Katy added: ''Me and Bonnie secretly did some background vocals on that song. So maybe listen for our voices.''

Other stars on the blue carpet at the Regency Village Theatre in Westwood, California, included Britney who brought her sons Jayden James and Sean Preston with her, Neil Patrick Harris - who plays Pat Winslow in the movie - Tamra Barney and Jayma May, who portrays Pat's wife Grace Winslow.