Evander Holyfield -- I Punched a Pregnant Horse in the Face

Evander Holyfield says he punched a pregnant horse in the face ... and he wasn't joking.

Holyfield made the shocking confession during tonight's episode of UK Celebrity Big Brother ... and an hour later he was BOOTED from the house.

The ex-heavyweight boxer told his horrified roommates ... the pregnant horse bucked him off and embarrassed him ... so he clocked it in the face.

You gotta watch the video ... and then reconsider the way you felt when Mike Tyson bit his ear off.