The Irish music manager had previously said he was keen to join Simon Cowell and Cheryl Cole on the judging panel for the 11th series of the talent show, but was still in negotiations about his contract.Walsh, 61, has now revealed on the Colm Hayes show on 2FM that he has done the deal.He revealed: "I knew I was doing the show but I just signed the deal and I'm very happy with it. At my age you have to keep working!"It had been rumoured that Cole - who is returning to the show after three years - was not happy about working with Walsh.CHAR(13) + CHAR(10)Cowell had said: "I would love Louis to come back and do the show, it wouldn't be the same without him."Other people have different views, so we have to agree on it."The fourth judge is still to be announced, although Spice Girl Mel B - who has previously made guest appearances on the panel - is said to be the frontrunner.Walsh said: "It has to be someone I like. I'd love it to be Sharon Osbourne, but I don't think it's going to be her. There are all sorts of rumours going around."I think it could be Mel B from the Spice Girls. I love her and she's quite mad. She also did both the American version and the Australian versions of X Factor."Walsh admitted fatherhood had "mellowed" Cowell, but insisted he will not be vying to take his title as TV's Mr Nasty.He said: "I definitely don't want to be the hard guy. I'm going to try to be the sunny guy and put all the Irish acts through."