Former 'Voice' Contestant -- Cee Lo's No Sex Criminal

Cee Lo is nothing but a professional, respectful gentleman ... at least on the set of "The Voice" -- so says a former contestant on the judge's team, who also happens to be female.

42-year-old Terisa Griffin -- who was eliminated from Cee Lo's team last week -- tells TMZ, "He was a lot of fun and even complimented me on my engagement ring. Cee Lo was extremely professional, not a drop of disrespect."

Teresa adds, "I was shocked to hear about the investigation."

As we first reported, Cee Lo is currently the target in a sexual battery investigation, after a woman claims the singer drugged her and then sexually assaulted her.