Carell, who played the boss in the Americanized version of the iconic British series, left the show last spring after seven seasons to focus on his family and film career.
He was nominated for an Emmy Award last week for his portrayal of havoc-wreaking, but lovable Dunder Mifflin regional manager Michael Scott. NBC recently announced James Spader would be leading the cast in Season 8.
"I can't wait. I can't wait. I think it'll be great this year. I think James Spader was an excellent choice," Carell told United Press International in New York Monday, while promoting his new film "Crazy Stupid Love."
Told he will be irreplaceable on "The Office," Carell insisted: "That's kind of you to say. I don't agree."
Asked if he is looking forward to catching up with his former cast-mates at next month's Emmy Awards show, Carell replied, "Oh, I'll see them all the time."
"I just got e-mails from Phyllis [Smith] and Rainn [Wilson,] talking about how they're going back in a week or two weeks. That's the weirdest part is that all my friends are going back to school," he said. "And I graduated."
Carell will next be seen on the big-screen in "Crazy Stupid Love," starting July 29.
In the movie, he plays a long-married family man who finds himself thrust back into the dating scene after decades because his wife, played by Julianne Moore, has cheated on him and asked him for a divorce. The film co-stars Ryan Gosling, Emma Stone, Marisa Tomei and Kevin Bacon.
Carell's other film credits include "Despicable Me," "Little Miss Sunshine," "The 40-Year-Old Virgin" and "Evan Almighty."