Bill Maher has issued an apology for using the N-word on Friday’s edition of HBO’s “Real Time with Bill Maher.”

Maher said in a statement: “Friday nights are always my worst night of sleep because I’m up reflecting on the things I should or shouldn’t have said on my live show. Last night was a particularly long night as I regret the word I used in the banter of a live moment. The word was offensive and I regret saying it and am very sorry.”

A rep for Maher said the comedian was traveling on Saturday and unavailable for further comment. He is scheduled to do a comedy performance at Indianapolis’ Murat Theater on Sunday.

The storm around Maher’s use of the phrase “house n—–” during an interview segment has been building via social media ever since the show’s 10 p.m. East Coast airing. The incident prompted some to revisit past statements from Maher about Muslims and LGBTQ people that have been widely deemed offensive.

HBO is facing calls to fire Maher. The cabler issued a statement Saturday calling Maher’s choice of words “completely inexcusable and tasteless” but stopped short of any formal sanction against the host. Maher’s apology came about two hours after HBO’s statement. According to a source, Maher was surprised by the volume of the backlash but was also motivated to take the highly unusual (for him) step of issuing a statement out of sincere regret.

As of Saturday afternoon, “Real Time” is expected to air next week in its usual 10 p.m. Friday slot.