Stephen Colbert reportedly in line to replace David Letterman on the Late Show

The satirist is rumoured to be the top contender to take over from the legendary US chat show host

Stephen Colbert will be leaving his persona behind and simple being himself for the Late Show, insiders have said (Getty Images)

Stephen Colbert is reportedly in the running to replace David Letterman on the Late Show.

Sources told Mashable that the comedian is the "front-and-centre candidate" for the job and that Colbert was "first engaged with network executives" when Letterman was considering stepping down.

Network CBS is said to have spoken to a number of other people, including Colbert's The Daily Show co-star Jon Stewart. However, there is apparently only one man for the role.

"Colbert would leave behind the pseudo-conservative persona he's cultivated at The Colbert Report and just be himself at his CBS home," the source said.

Colbert is best known for his correspondent persona on Comedy Central's satirical programmes The Daily Show and his spin-off series The Colbert Report.

Veteran talk show host, Letterman, announced his retirement on Thursday, during the recording of the Late Show with David Letterman, telling the audience that he wanted to spend more time with his family.

He said: "I just want to reiterate my thanks for the support from the network, all of the people who have worked here, all of the people in the theatre, all the people on the staff, everybody at home, thank you very much. What this means now, is that Paul and I can be married," in reference to the Late Show's long-time band leader, Paul Shaffer.

The announcement was met with outpourings of sadness and accolades for Letterman, with US President Barack Obama tweeting: "There are more than 10 reasons #DavidLetterman will be missed."

The Late Show with David Letterman launched back in1993 and has been a fixture on American television for over two decades.

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Letterman has interviewed countless stars from Madonna to Harrison Ford to Drew Barrymore, who famously flashed her breasts at the host mid-way through a show in 1995.