Bill Maher is out one big guest for his next live show on HBO this Friday -- Senator Al Franken just canceled his appearance.

Franken announced Monday he won't be appearing alongside Maher for Friday's episode. A spokesperson for Franken said Maher's use of the n-word last week was the reason.

A spokesperson for Franken tells us, "Senator Franken believes that what Bill Maher said was inappropriate and offensive ... He was glad to see Bill, who the Senator considers to be a good friend, apologize and express sincere regret for his comment."

This would seemingly be the first real professional consequence Bill has faced since using the racial slur. As we reported, HBO isn't going to can him ... and his tour dates are fine for now.

Ice Cube is also scheduled to appear on Maher's show this week. Unclear if he'll go through with it.