If you've been following the saga of "BFFs for six months" Stephen Colbert and Jimmy Fallon, you'd know that last week Colbert pledged $26,000 of Fallon's money to the charity DonorsChoose.org, but without asking Fallon first.

Fallon responded Monday to this by announcing that if he could raise that $26,000 from the public, then Colbert would be forced to appear on 'Late Night With Jimmy Fallon' and sing Rebecca Black's viral sensation 'Friday' with The Roots.

"What the f**k?" Colbert said on Tuesday's 'The Colbert Report' (Weeknights, 11:30PM ET on Comedy Central), after playing the clip of Fallon saying that $26,000 buys the public a singing Colbert.

Fans of 'The Colbert Report' know that Stephen Colbert recently raised $26,000 for Donors Choose at an art auction. They also know that he announced on his show that his "best friend for six months" Jimmy Fallon of 'Late Night' (Weeknights, 12:37AM ET on NBC) would be matching that donation.

Unfortunately, fans of 'The Colbert Report' knew more than Jimmy Fallon did. Tonight, he shared that clip with his audience and they applauded it. "But here's the thing," Fallon said. "I never said that."

At this, Colbert himself came onto the set to set the record straight. "If you can't donate $26,000 of your best friend's money without asking him first, then what's the point of being best friends?" he asked.