Not even a contest. Debbie Gibson. Only because I hated the song "Could've Been" and thought Tiffany was kinda skanky – but that was years ago before they gave us this SyFy non-blockbuster:
Yes, that's a real movie. I watched it. It was horrible bad. But what would you expect from Debbie Gibson AND Tiffany in a made-for-tv movie called Mega Python vs. Gatoroid? One of them was a scientist or something. I wish I were kidding. You know who else was in that movie? GIANT BAD CGI SNAKES AND GATORS.
And here's the cat-fight scene from the movie: