The 'Teenage Dream' hitmaker – who was recently a guest judge alongside the Girls Aloud singer, Louis Walsh and Simon Cowell on 'The X Factor' – is in awe of the 'Fight for This Love' hitmaker and would love to romance her if she wasn't in a relationship with Russell Brand.
Katy said: "I adore Cheryl – she's amazing. I'm very happy with my own English stud but if I wasn't with him I'd be trying to date Cheryl.
"Nobody should be as beautiful as she is. I know people get turned on by Simon's power but if I was single I'd rather sleep with Cheryl than Simon."
The US star also hinted that Cheryl has landed a role on the US version of 'The X Factor' – which is set to launch next year – and says she would love for them to work on music together.
She added: "After 'The X Factor US' I think she'll be a fashion icon. The US is going to love her – and I want to perform with her."