Schwimmer, 43, is best known for his work on TV's "Friends," but he has also appeared in the film "The Pallbearer" and lent his voice to the character of Melman the giraffe in the "Madagascar" movies.
The actor's representative confirmed his engagement to Buckman, 24, to Entertainment Weekly exclusively.
Schwimmer reportedly met Buckman in London while he was directing the 2007 big-screen comedy "Run Fatboy Run."
Couple calls 9-1-1 over missing hash browns; assault McDonanld's employees
Britney Spears debuts 'Perfume' video