Broadway stars Deborah Gibson and Sharon McNight will join the cast of the national tour of Mamma Mia! for a special One Night Only Cabaret at 7:30pm on Monday, September 10 at San Francisco's Club Fugazi. Proceeds from the event will benefit Broadway Cares/Equity Fights AIDS.

Mamma Mia!, the hit musical featuring the songs of ABBA, will play San Francisco's Orpheum Theater, September 5-22. Gibson has appeared on Broadway and in London in such musicals as Grease, Beauty and the Beast, and Cabaret. McNight received a Tony Award nomination for Starmites and is one of the country's most popular cabaret performers. She will appear at San Francisco's Empire Plush Room, September 14-23.

Tickets range from $20-$75. To order, call 415-421-4222.