O'Brien's new program will air at the same time as the "Late Show with David Letterman", "The Daily Show with Jon Stewart" and "The Tonight Show", which saw Jay Leno regaining hosting duties after O'Brien left NBC earlier this year.
Stewart may be O'Brien's biggest competition. In October, The Daily Show averaged 1.3 million viewers aged 18 to 49, while Letterman and Leno's program were seen by about 1.2 million people from that demographic, marking the first time the latter two have been beaten by a talk program since 2000.
O'Brien, who succeeded Leno as "The Tonight Show" host in 2009 after hosting NBC's subsequent talk program Late Night, since 1993, has been most popular among young adults.
"Just tried on my suit for tomorrow's premiere," O'Brien wrote on his Twitter page on Sunday. "I have twelve hours to lose 35 pounds. Tomorrow, I'll be back where I truly belong - indoors, under artificial light."
During O'Brien's seven-month stint as "The Tonight Show" host, Leno helmed a new talk program that aired earlier. Following lackluster ratings and local affiliate disagreements, NBC had proposed that both programs be moved to later.
O'Brien declined NBC's proposal and left the network. The time slots of the shows remained unchanged and Leno, who hosted "The Tonight Show" between 1992 and 2009, regained the position in March. The relationship between the two hosts is said to be icy.
"He can come as the musical guest, because that I want to see - no one knows he has an operatic range," O'Brien joked about Leno in an interview with Playboy, according to The Hollywood Reporter. He later said, "No, there are certain things I will not do, regardless of the price."
Seth Rogen has been announced as the first guest of Conan. Other appearances include Tom Hanks - who gave the comedian his Coco nickname, Jon Hamm, and Michael Cera, as well as "30 Rock"'s Jack McBrayer, comedian Charlyne Yi, and Modern Family's Julie Bowen.
The new talk show will not see the return of longtime drummer and bandleader Max Weinberg, who has often taken time off to tour with Bruce Springsteen's E Street Band. Guitarist Jimmy Vivino has been named as the new bandleader for O'Brien's show, while James Wormworth will play drums.
Last week, O'Brien recently released a YouTube video dubbed "Show Zero", touted as the "fastest talk show ever", to promote Conan as well as Diet Coke. During the segment, which lasts a little under five minutes, O'Brien walks through an office, introduces a piccolo player from his band, recites jokes and interviews Jim Parsons, star of CBS series The Big Bang Theory, for several seconds.
Past promotional clips have shown O'Brien washing his desk and making sexy poses to Def Leppard's "Pour Some Sugar on Me" and driving a car filled with explosives and popcorn off a cliff.
- Corinne Heller