He asks Ellison about the recent controversy in which Rep. Michele Bachmann, R-Minn., suggested that Ellison could be linked to the extremist Muslim Brotherhood. Her allegations were roundly criticized.
Tongue firmly in cheek, Colbert has Ellison acknowledge that he is Muslim and that he has siblings.
"So you are literally a Muslim brother," the satirist says.
Colbert also asks the Minneapolis congressman why Mary on "The Mary Tyler Moore Show" couldn't ever find a nice guy. Here's the clip: