The good-looking Welsh presenter has been picked over the British show's host, Dermot O'Leary, who was reportedly told he wouldn't be picked because the network were looking for an American.
Simon Cowell has already been heaping praise on his two new hosts, telling the Daily Mail: 'I have always wanted Steve to work with us; I think he is a real star. Nicole is fantastic. I loved working with her on the UK X Factor last year. She is gorgeous and super-talented.'
And Steve says of his new job: 'The ability to work day in and day out with Simon Cowell is a dream come true. I am honored to have that opportunity and thrilled to be able to share the stage with Nicole Scherzinger, whom I adore.'
He added: 'I have been approached about working in the States before, but never felt right about those opportunities.'
Steve, who left Channel 4 in November after ten years there, recently said: 'Of course I would love to do it. I'm a big X Factorfan. It's one of the biggest - probably the biggest - jobs in presenting at the moment.'
Cheryl arrived in America today, ready for the first round of auditions in LA, while Paula Abdul is reportedly in last-minute negotiations to join her on the judge's panel.