The 39-year-old, who has played Jacobite soldier in five series of Outlander to date, broke the news when asked about speculation by American talk show host Jimmy Fallon.
However, speaking on The Tonight Show, Heughan said it was "definitely time for another Scottish bond."
Bookmakers have slashed odds on Heughan, from Dumfries and Galloway, following in the footsteps of fellow Scot Sean Connery in recent weeks after a flurry of bets were placed.
Heughan was named favourite ahead of two other Scots actors, Richard Madden, who shot to fame in Bodyguard last year, and Mary Queen of Scots star Jack Lowden.
Tom Hardy, Michael Fassbender, Tom Hiddleston, Idris Elba and James Norton are among the other leading contenders, according to leading bookmakers.
Heughan was asked by Fallon about being on "the top of many lists" to become the next Bond, and his backing for the role by Star Trek legend William Shatner.
Heughan said: "I can reveal right now that I...am not James Bond. I'm still waiting for the call."
After the clip was shared on social media, Heughan told his 561,000 Twitter followers: "Not sure Bond could be ginger...?"
Heughan was appearing on The Tonight Show ahead of the launch of the fifth season of Outlander on Amazon Prime in February.