Seal Looking Hot ... Under the Collar

Seal single and at LAXJust hours before TMZ broke the story about Heidi Klum gearing up for divorce, Seal arrived back in L.A. after a quick trip to London -- wearing massive shades, a red scarf, an enormous-collared jacket, and a grim expression.

As TMZ first reported, as of Sunday night ... Heidi and Seal are still living under the same roof.