Or at least, it's a strong contender. William Shatner would be embarassed by this amateurish seduction of an alien. In this clip, you'll see: 1) An alien in a jumpsuit with pom-poms sewn onto her breasts. 2) The alien randomly stripping behind a screen for no reason. 3) Perry Rhodan clumsily putting his moves on her. 4) Weird Alpine yodeling music.
This clip comes from 1967's Mission Stardust, widely regarded as one of the worst space-opera movies of all time. It's theoretically an adaptation of the long-running series of Perry Rhodan novels, but is mostly just an excuse for wooden acting, stock footage of rockets interspersed with model work, and ludicrous aliens. Plus there's a whole other plot which barely connects with the "aliens seeking to rejuvenate their race" storyline, involving a supervillain who wants to steal a rare metal from the Moon.
Here's an amazing moment where the supervillain is holding a floppy puppy in one hand and getting a manicure on the other, for some bizarre reason: