Soul singer Toni Braxton is battling breast cancer, according to U.S. tabloid reports. The Unbreak My Heart singer, who is currently wowing fans as the star of a Las Vegas stage spectacular, is secretly undergoing radiation treatment and chemotherapy, according to the National Enquirer. Mum-of-two Braxton reportedly received her terrifying diagnosis two months ago, but chose to keep her cancer fight to herself after doctors insisted she'd caught the disease early enough to beat it. And she decided her Toni Braxton: Revealed show at the Flamingo hotel and casino must go on too, so doctors have been pumping an iron infusion into her twice a week to combat the fatigue caused by her chemotherapy, according to the Enquirer. A family source tells the publication, "Toni is a fighter. She initially thought the worst, but doctors assured her the prognosis for her breast cancer is excellent. "She still has moments when she gets upset and she may cry a little bit - but those moments don't last long." It's not the first health crisis for the 40-year-old six-time Grammy winner - she was diagnosed with heart condition pericarditis in 2002 after she passed out backstage at Broadway musical Aida.