We're told Tamar started feeling ill earlier this week while promoting her new album, "Bluebird of Happiness," in New York. She bowed out of several public appearances because she could barely speak, prompting her to see an ear, nose and throat doctor.

She was prescribed Prednisone, a steroid for her throat, but her body had a horrible reaction and swelled up. The swelling was so severe once she returned to L.A. she was rushed to the ER on Wednesday night.

Tamar later posted a picture from her hospital bed with her hospital band asking for prayers. We're told she's expected to stay in the hospital for a few days until she makes a full recovery.

Get well soon!