Katy Perry 'quits coffee' for tour.

Katy Perry has quit coffee in preparation for her 'California Dreams' tour.

On Twitter the singer wrote 'Today I quit my beloved coffee & make the switch to vitamin B complex. Don't worry @starbucks it's not forever. #tourtourtour.'

The singer has previously posted about her diet regime, Twittering in January:'I cheated on my meal plan with McDonalds breakfast. I'm sorry, I just had to'

Katy's promising bells and whistles and 15 costume changes on her California Dreams tour.

The Firework star also told Rolling Stone that fans will enjoy a 'sweet' gig.

"It's the first concert that's going to smell good - it's going to smell like you're in cotton candy heaven," she told Rolling Stone.

"It's a fun little nuance. I am a woman of detail, and you will be seeing that - even down to the 15 outfit changes I'm doing in concert."