Tom Cruise revived the overweight studio exec character from "Tropic Thunder" Thursday night on Conan O'Brien's show at Comic-Con in San Diego. 11 years later and Tom has NOT lost the famous dance moves that catapulted Les into legendary status.

Tom made a surprise appearance at Comic-Con to promote the first "Top Gun: Maverick" trailer -- which looks SICK, BTW -- and later stopped by "Conan" to reminisce about the Ben Stiller-directed action-comedy.

Ya gotta watch ... after busting out the dance moves and explaining how that sequence all came about ... Tom summed up the glory days by busting out Les' signature cursing dialogue -- at Conan's request. Tom obliged.

Tom, of course, dropped the classic Les line -- "Would you stand back and literally f*** your own face?!?" -- during a scene with Matthew McConaughey as Rick Peck.