A man flirts with a woman in a bar, then follows her out and matches her steps from behind, as she coyly looks back.
Cut to his bedroom, where she's undressing for him as he lays watching. The lingerie falls and we see she's wearing men's underwear--he smiles acceptingly as he sees it's not actually a woman. The Bee Gee's song "More Than A Woman" crescendos and the words
"Underneath it all I'm still a man" appear over the black underwear.
Inspired by "The Crying Game" film about a cross-dresser, this British ad is very positive in its portrayal because there is no negative implication to the revelation that it is in fact a man...it actually seems a good thing.