Brennan Linsley, File, Associated Press
In this Jan. 17, 2015 file photo, comedian Bill Cosby performs at the Buell Theater in Denver.

BOSTON — Bill Cosby has cancelled his Sunday stand-up comedy performances in Boston.

The Wilbur Theater posted an announcement on its website Sunday morning. The theater said tickets will be refunded where patrons purchased them. It apologized for the abrupt change but did not say why the two shows were cancelled.

Women's groups had been expected to rally in opposition to Cosby's shows. An actress who appeared in an episode of "The Cosby Show" is expected to hold a news conference at a Boston hotel Sunday afternoon to talk about sexual advances she alleges the 77-year-old entertainer made.

Cosby faces sexual assault accusations from at least 15 women. He denies the allegations and has never been charged with a crime. Some of his performances elsewhere have drawn protests. Some have been canceled.