Danielle Knudson did an oceanside photo shoot for H&M -- but we're not sure what the hell she's advertising ... besides her half-naked body all covered in sand.
The Canadian model hit up a beach in Tulum, Mexico Wednesday for a shoot with the beleaguered Swedish retail company, where she started off in a 2-piece bikini, and ended up topless ... layered with sand ... and on top of some very lucky dude.
We imagine they were showing off some of H&M's swim line -- but it's anyone's guess with how much skin is showing here. At least it ain't "monkey in the jungle" Winter wear again.
Fun fact: it's officially Spring ... which means we're coming up on bikini season! Not-so-fun fact: Danielle is taken ... damn.