The Twilight star's elder sibling showed off her own skills during an audition for the upcoming season of the hit talent show, and even passed the first round in front of judges Simon Cowell, Cheryl Cole, Melanie Brown and Louis Walsh.
Pattinson couldn't be more proud of his sister, gushing to The Huffington Post, "I'm like, so ridiculously proud of her. I would never have the balls to do that, ever, in a million years. I can't believe she's done it. So, it's amazing."
In addition to loaning her voice to a number of dance tracks in the early 2000s, Lizzy also contributed background vocals to the Twilight scores.
The 11th season of The X Factor in the U.K. kicks off later this month (Aug14).