It's not such a great day, America - not for fans of Craig Ferguson.

Ferguson, TV's kinetic Scottish presenter, brings to a close his decade-long run as host of CBS' The Late Late Show tomorrow.

Airing at 12.35am EST, he concludes a grand stretch of silliness and smarts that, while never posing much of a ratings threat to talk-show rivals, struck a chord with a loyal following (and earned him a coveted Peabody Award for his 2009 interview with - of all people - Archbishop Desmond Tutu). Smarts with silliness.

Ferguson told viewers he was stepping down last April.

"CBS and I are not getting divorced, we are consciously uncoupling," he said, echoing the words of estranged Gwyneth Paltrow and Chris Martin.

This was no surprise since, weeks earlier, David Letterman had announced he was retiring from Late Show, whereupon CBS tapped Stephen Colbert to replace him. Once upon a time, Ferguson had been thought a strong contender for that job.

But The Late Late Show began fading in the ratings, particularly with the arrival of Seth Meyers last February as his NBC competition.

Ferguson's imminent departure is being upstaged by the much-anticipated, much-lamented exit today by Colbert as host of Comedy Central's The Colbert Report.

He will step into his Late Show role sometime after Letterman's sign-off on May 20.

Taking Glasgow-born Ferguson's place as host of The Late Late Show is British actor-writer-comedian James Corden, who debuts on March 9.

During the two-month interim, a slate of guest hosts - including Drew Carey, Will Arnett, Wayne Brady, Jim Gaffigan, Billy Gardell and Sean Hayes - will fill in.

But Ferguson, 51, will not be absent from the airwaves. This autumn, he launched Celebrity Name Game, a weekday syndicated game show.