The singer is set to debut her new single Womanizer on the ITV talent show later this year.
And Simon, 48, is confident that it will be a huge success.
‘She's got a record coming out. We have the number one show in Britain. It's the best show for her to perform on,’ he tells Us Weekly.
‘We're absolutely thrilled to have her. She's a hugely talented person. She's the number one booking in the world at the moment.’
Meanwhile, US reports claim Brit, 26, is considering getting back with ex-husband Kevin Federline, 30.
The pair - who have sons Jayden James, 2, and Sean Preston, 3 - are rumoured to be having counselling sessions.