Penn & Teller's magic act vanished from Las Vegas this weekend ... Penn Jillette was sidelined due to an ankle injury.

Penn took to Facebook to announce the news Saturday, writing, "We are sorry to have to cancel this weekend's shows. I broke my ankle yesterday and on doctor's orders, I am not able to do the show."

He added ... "Thanks so much for understanding and we hope to see you soon."

Of course, the iconic duo has been wowing audiences for 50 years now, performing nearly 300 live shows every year. Their show was called "The single best show in Vegas" by the Los Angeles Times, and their hit series "Penn & Teller: Fool Us!" -- where up-and-coming magicians try to fool the famous pair -- has been renewed for a 12th season.

The good news is, tickets are still on sale for this upcoming weekend, suggesting Penn expects a quick recovery.

Next week, they're expected in Fort Myers, Florida.