Charlize Theron surprised a boxing champ on his birthday -- threw punches at him and then kissed his face ... and we've got footage of the whole thing!
The man on the receiving end is Chris van Heerden -- a former IBO Welterweight champ who's a BIG fan of the actress (they're both from South Africa).
Peter Berg -- the mega-producer who owns the gym -- wanted to surprise Chris on his birthday so he got Charlize to swing by for a sparring session ... and Chris LOVED IT!