Ashton Kutcher's debut as the new lead in CBS sitcom Two and a Half Men has won the show its highest ever ratings, securing a successful comeback for the series that sensationally sacked Charlie Sheen.

A huge 27.7 million viewers tuned in to see Kutcher play a new character, billionaire geek Walden Schmidt, as Sheen's millionaire playboy Charlie Harper was unceremoniously killed off off-screen.

Two and a Half Men was already US TV's biggest comedy, but the Kutcher debut broke the show's ratings record. It also made Two and a Half Men the highest-rated season premiere for a scripted series since Desperate Housewives premiered six years ago, according to US newspapers.

Ashton Kutcher replaces Charlie Sheen on Two and a Half Men

Charlie Sheen's rant: Two and a Half Men producer's a "turd"

However, the last laugh could still go to Sheen after gossip website TMZ reported the actor is close to sealing a $125m settlement with producers Warner Bros.

Sheen, who was sacked from Two and a Half Men after his infamous soundbite-rich breakdown earlier this year, is apparently set to receive a lump sum of $25 million over the next few weeks.

However, the "tiger-blooded" star could get five times that amount overall owing to syndication rights for the show over the next seven to 10 years.

Warner Bros has denied there is to be a settlement.

When Sheen was fired he was the highest-paid actor in TV, raking in a sizeable $1.2 million per episode.

But his very public outbursts against the show's creator Chuck Lorre and Warner Bros resulted in his being fired midway through filming the last season.