Speculation over who will form the US version's judging panel has been rife - with Cheryl Cole among the names rumoured.
Speaking to his ex-girlfriend Terri Seymour on Extra, Cowell teased: "I'm going to make an announcement within three or four weeks, which is going to tell everyone everything.
"There will be some surprises."
Asked if he could elaborate on any of the judges, he dropped one hint, telling Seymour: "Okay, one of the judges has quite long hair."
Cowell was awarded the 'International Emmy Founders Award' at a ceremony earlier this week in New York.
> Dermot O'Leary 'in talks for X Factor USA'