The real-estate mogul recently began to air television commercials in both Iowa and New Hampshire to promote his candidacy.
The Iowa caucuses are set for Feb. 1 and the New Hampshire primary is Feb. 9.
Trump was last seen on The Tonight Show on Sept. 11. He and Fallon appeared in a comedy clip that went viral. In it, Fallon dressed like Trump -- complete with reddish, blonde hair and heavy facial makeup -- and pretended to be the reflection in a mirror interviewing the newbie politician.