Craig Ferguson Leaving Late Late ShowCBS is down one more late-night host — Craig Ferguson just announced to his studio audience that he would not be re-upping his contract to host Late Late Show and will step down in DecemberCBS and I are not getting divorced, we are ‘consciously uncoupling,’ but we will still spend holidays together and share custody of the fake horse and robot skeleton, both of whom we love very much,” Ferguson said in the announcement, which immediately triggered speculation as to who would replace him.

Ferguson is sticking around until year’s end to give show staff time to figure things out, according to a source with knowledge of the situation. But, with Ferguson leaving in December, it’s likely CBS will have a new 12:35 AM host on its air before Stephen Colbert replaces David Letterman — Colbert is likewise leaving his Comedy Central series The Colbert Report at the end of the calendar year, but David Letterman has yet to set his end date on Late Show — only saying it will be some time in 2015.

Ferguson has been Late Late Show’s host since succeeding Craig Kilborn in January 2005; his contract was set to expire this summer, so it had been widely expected some decision on his CBS late-night future would be reached soon-ish. And all America recently was brought up to speed on the clause in that contract that landed him a pot of cash if the network looked elsewhere for its David Letterman replacement.  That happened when CBS went with Stephen Colbert after Dave also surprised his studio audience with news he was stepping down in 2015.  But Ferguson was quick to tweet his congratulations to Colbert the morning the news broke. That night, Ferguson opened his show with another shout-out to Colbert, after which he teased viewers with cracks about resigning — but only for the length of a commercial.

While CBS Entertainment chief Nina Tassler had insisted publicly CBS loves Ferguson, CBS CEO Leslie Moonves recently acknowledged Ferguson’s time slot was up for grabs and said “we’re having conversations” but “there’s nothing to report now.” CBS execs were said to be frustrated that the numbers haven’t grown on Ferguson’s show, currently co-produced by CBS and Letterman’s Worldwide Pants, though others suggested that was just the rumblings of a network prepping its position should its star take a hike.

Today, Tassler said, “During his 10 years as host, Craig has elevated CBS to new creative and competitive heights at 12:30. He infused the broadcast with tremendous energy, unique comedy, insightful interviews and some of the most heartfelt monologues seen on television.” She added, “While we’ll miss Craig and can’t thank him enough for his contributions to both the show and the network, we respect his decision to move on, and we look forward to celebrating his final broadcasts during the next eight months.”

And ratings were only half the story: CBS, which will own Late Show when Letterman steps down (Worldwide Pants owns its current iteration), is hellbent on returning the daypart to greater profitability under Colbert. You may have heard the one about late-night TV profits curling up like the tendrils of a delicate plant ignored by the gardener in the later days of Letterman’s and Jay Leno’s runs, what with costs going up and ad revenue going down.

Throughout the process, CBS spent time initially denying it was talking to Chelsea Handler about replacing Craig, while her camp did its best to fan the flames. “There are no discussions with Chelsea Handler regarding the network’s 12:30 late night broadcast,” the network said after Handler posted a photo of herself taking a “business meeting” with CBS paperwork in her hand, conveniently turned around so the camera easily could read it. The CBS logo was visible as was the word “distribution” suggesting CBS Televisision Distribution — syndicator of Arsenio Hall’s late-night show.

Related: David Letterman On Stephen Colbert’s Hire

Meanwhile, Ferguson and his Green Mountain West Inc production house has been busy making late-night aftershows for various Discovery Network shows,  including Shark After Dark and Naked After Dark. Last month, Discovery’s Science Channel bought Ferguson’s I F-ing Love Science series — which has yet to name a host. That series is inspired by the popular Facebook page I F*cking Love Science, which has attracted more than 11M social media followers since it was created three years ago by British biology student Elise Andrew, who is onboard as a consulting producer. The series is produced by Green Mountain West and Karga7 Productions and will premiere in the fourth quarter, featuring a blend of live-action, animation, and re-creations showcasing the random connectivity of science with appearances by celebrities and scientists. Ferguson himself made the announcement via taped message at Science Channel’s SXSW Interactive event.

In December, DebMar Mercury announced the Ferguson-hosted Celebrity Name Game is set to launch on 58 Sinclair stations, four CBS O&Os and others, pushing clearances for the fall 2014 syndicated pop culture game show past 80% of the U.S — up from 40% in less than a month. Tribune Broadcasting previously came aboard, acquiring Celebrity Name Game for all 25 of its stations. The half-hour strip, based on the board game Identity Crisis, was developed by Courteney Cox and David Arquette’s Coquette Prods with Scott St. John (Deal Or No Deal), who will serve as showrunner. Ferguson’s involvement stems from the project’s first incarnation at CBS where Coquette sold it as a pilot two years ago under the title Identity Crisis with Ferguson hosting. Celebrity Name Game is co-produced and co-financed by FremantleMedia North America and Debmar-Mercury.

Meanwhile, here is how Ferguson recommended Jay Leno spend his last night as a late-night talk show host at NBC, before Leno left Tonight show, for the second time, in  February: