Ashton Kutcher admits he "can't replace Charlie Sheen" on 'Two and a Half Men'.

The 33-year-old star has been confirmed as the new lead star in the sitcom - from which Charlie was fired in March because of his erratic conduct - and has vowed to work his "ass off" to ensure the show is a success.

He said: "I can't wait to get to work with this ridiculously talented 2.5 team and I believe we can fill the stage with laughter that will echo in viewers' homes.

"I can't replace Charlie Sheen, but I'm going to work my ass off to entertain the hell out of people!"

Show creator and executive producer Chuck Lorre is thrilled that the hit comedy - which will resume filming in summer - is now able to continue after its future was thrown into doubt following Charlie's dismissal.

Chuck said: "We are so lucky to have someone as talented, joyful and just plain remarkable as Ashton joining our family.

"Added to that is the deep sigh of relief knowing that our family stays together. If I was any happier, it'd be illegal."

Meanwhile, Charlie - who branded Chuck "s**tbrain" and "Chucky Cheeseball" during their public feud - has taken a swipe at Ashton's appointment, insisting he will not attract the same demographic of viewers that he did.

Charlie told TMZ: "Kutcher is a sweetheart and a brilliant comedic performer. Oh wait, so am I!!

"Enjoy the show America. Enjoy seeing a 2.0 in the demo every Monday, WB. Enjoy planet Chuck, Ashton. There is no air, laughter, loyalty, or love there."

It has been confirmed that joining Ashton - who will be introduced as a new character, rather than a direct replacement for Charlie - in the show will be returning stars John Cryer and Angus T. Jones.