Penn & Teller's magic shows are on hiatus because Teller's back injury has flared up.

The duo canceled a performance in Mississippi on Friday, with Teller tweeting an apology to fans. He wrote he's stopping work until Aug. 18 and "getting my back surgery pronto."

Raymond Teller, who is 70, says he's "disoriented and befuddled" because he thinks they've had to cancel only four shows on short notice during their career.

They've worked as a pair since 1981.

Sixty-three-year-old Penn Jillette wrote "the boys will be back and bad!"