CNN Business  — 

Brian Williams, who helped put MSNBC on the map 25 years ago, is about to exit the cable news network.

He is signing off from his 11 p.m. Eastern program, “The 11th Hour,” for the final time on Thursday night, a network spokesperson confirmed.

Williams has been alluding to his departure date during segments with some of his regular guests, and viewers have been tweeting out tributes to him.

“The way you handle discourse in these difficult times,” guest Baratunde Thurston said last Thursday, “is a model for a lot of what we all will need to do more of.”

Williams has anchored “The 11th Hour” for the past five years. He announced last month that he is leaving MSNBC and NBC News to pursue new opportunities — a striking departure given his long-term ties to the company.

In last month’s announcement of his departure, Williams expressed deep gratitude to NBC, saying the network is “a part of me and always will be.”

MSNBC’s schedule on Friday lists the premiere of a documentary, “Paper & Glue,” in place of Williams’ program.

Starting Monday, “The 11th Hour” will be anchored by a rotating group of guest hosts, a network spokesperson said.