My Hero (2000)

The course of true love never did run smooth, but it's bumpier for mild-mannered health food shop owner George Sunday than most. He'd like nothing more than to spend quality time wooing his girlfriend, Janet Dawkins, but George has a secret: He's actually Thermoman, a superhero from another planet, and how is a bloke supposed to pitch woo when he's constantly having to save the Earth from one interplanetary menace or another?