Robbie Williams has only two years of being a pop star left.

The 'Candy' hitmaker reaches the milestone age of 40 in 2014 and thinks that will mark a point where his career is viewed in a different light.

He said: ''I'm 40 soon so I've got two years left of being a pop star and then I become an old man on stage singing.''

Robbie - who became a father to daughter Theodora 'Teddy' Rose in September - also admitted he had turned to the gym as he panicked about his physique ahead of promoting his new album 'Take the Crown' when he began piling on weight after quitting smoking, though he now thinks he has gone too far.

Speaking on stage at the Marmite Christmas Lights switch on in London's Oxford Street, he said: ''I went from smoking three packs a day to none, and I put on some weight and knew I wasn't going to be able to lose it in time to promote the album.

''So I just started pushing weights and now I look like a doorman.''

While Robbie and wife Ayda Field are looking forward to their first Christmas with Teddy, he won't be buying her any gifts.

He admitted: ''It's Teddy's first Christmas, so that's going to be really special. But she's too young to remember anything, so she won't be getting any presents.''

Also performing at the Marmite Christmas Lights switch on were boy band Lawson and Leona Lewis.

The evening was hosted by Heart FM DJs Jamie Theakston and Emma Bunton.