The 25-year-old singer is currently promoting her new single California Girls. She is due to be interviewed by celebrity reporter Ryan later this week, and has promised to flash some flesh in skimpy clothing if Ryan joins her. Katy is so keen to see the presenter in his smalls she has started a Twitter campaign to pressure him into agreeing.

“I'll show up in daisy dukes & a bikini on top 4 tomorrows interview w/@ryanseacrest IF HE DOES. You want 2 see this mess happen? RETWEET! (sic),” Katy wrote on her page on the social networking site.

Ryan was keen to play along with Katy, posting a reply within seconds. It read: “OK. What colors? Katy also took to her Twitter account last night to tell 16-year-old Canadian pop star Justin Bieber to eat more healthily. Katy jokingly asked her fiancé Russell Brand if they could adopt the young star earlier this year, and is taking her new role as “adopted mother” very seriously.

When Justin posted that he has just enjoyed a fast food feast last night, Katy promptly replied: “Eat your spinach young man! -adopted mother.