Heidi Klum's Bodyguard Protecting Heidi's Body ... Just Last Week

9/4/2012 7:39 AM PDT

Heidi Klum
and her bodyguard returned from Spain together just last week ... looking more like a couple than a boss and her employee.

The footage of Heidi and Martin Kristen was taken at LAX on August 28 ... after coming back from a trip to Sardinia ... where the two were seen looking pretty affectionate on the beach.

We broke the story ... Seal claimed Klum was bangin' Kristen while she was still with the singer, though Heidi insists there was no such fornicating while they were together.

Seal used Kristen to guard HIS body as recently as last month ... though we're guessing those days are over ... 'cause it's probably really awkward now.