Amber Heard Leaves Gala After Medical Emergency

Amber Heard made an unexpected and sudden exit from an awards gala last night because of a medical emergency ... TMZ has learned.

Heard was scheduled to be honored at the unite4:humanity gala in Beverly Hills Friday night but left midway for what we're told was a medical emergency. Our source says Heard became seriously ill during the event, but it's unclear if she went to the hospital.

Friends Cara Delevigne and iO stepped on stage to accept the award on her behalf.