In addition, a cash prize of £500,000 will be on offer for the winner including £250,000 of Cowell's own money.
On returning to the panel, Cowell said: "I miss Britain and I miss the British public and I miss judging them. I want to find the next generation of talent in 2012. Different and new acts, younger and better talent. You want someone who can be a star all over the world and by coming back in 2012, it's the year of the Olympics, it's a big year for Britain, we are going to be in the world's spotlight and I want this show to be back in the world spotlight."
Cowell is excited about welcoming fresh blood to the judging panel but has already taken a dig at David Walliams.
He said: "I'm absolutely delighted David is joining the panel. He thinks he can do a better job than the people there before so it's going to be fun. I think he's terrified!"
On Dixon, he said: "I love Alesha. She is feisty, opinionated and knows what it's like to be both a competitor and judge on a hugely popular TV show. This is going to be a brand new experience for her and I think she is going to bring a lot to the table."
Funnyman Walliams is looking forward to stepping into the shoes of one famous talent show judge but someone might want let him know that he's not joining The X Factor.
He said: "I am so thrilled to be the new Cheryl Cole."
Cowell hopes that the level of talent competing for a place on the show will rocket with the prize fund increasing from £100,000 to £500,000. The winner will also appear at the Royal Variety Performance in 2012.
In addition to the new judging panel, the show's format will be changing slightly with the first open audition in association with Virgin Media being held at London's Oval on Sunday 22nd January.