The auditions will the first event to be held at the new venue, which officially becomes London's first international convention centre (ICC) on 1 May, ahead of its official launch party in June.
James Rees, director of conferences and events at Excel London, said: "Winning the contract to host The X Factor auditions is a real coup for both the ICC and the team."
"It is a fantastic way to introduce the ICC London Excel to the world. With such a high profile event, the sheer number of people that it will attract to the new facilities and the millions that watch the show, make it the perfect showcase for us."
Last month, Excel London announced it had won £6m of events business since being named as London's first ICC last October.