Crucial to any disappearing act is the reappearing. Penn & Teller are going dark at the Rio on July 10 and will return on Aug. 18.

Penn & Teller, the comedy duo that perform at the Rio, are going dark for five weeks this summer while Teller undergoes back surgery. (Caesars Entertainment)

Penn & Teller are shown with a large cake at the RIo, commemorating their 25th anniversary of performing in Las Vegas, on Sunday, Jan. 14, 2018. (Glenn Alai)

Crucial to any disappearing act is the reappearing.

Penn & Teller are going dark at the Rio on July 10 and will return on Aug. 18.

Teller, 70, to undergo spinal fusion surgery next month to address chronic symptoms of hanging upside-down in straitjackets and otherwise climbing in and out of boxes in a 40-year stage career.

During this “dark,” Penn Jillette is undergoing a medically supervised water-only fast.

As the vocal member of the comedy-magic duo, Jillette said today on Twitter, “Yes, we will NOT being doing our show from July 10 – August 18th. Teller needs back surgery and I’ll be doing a medically supervised water-only fast. We’ll be back super-healthy! Sorry for changing anyone’s plans.”

He later added in a separate post, “Oh, the time is for Teller to heal completely, I won’t be on a water-only fast for the full five weeks, of course. Medically supervised and just long enough to give some help to my blood pressure. Not for weight.”

Jillette, 63, has famously dropped 100 pounds through a strict vegetable-based diet over the past three years. He has held his weight at about 220 pounds.

Away from the stage production, Penn & Teller’s show “Fool Us,” recorded in March at the Rio’s Penn & Teller Theater, returns 8 p.m. Monday on The CW. Piff the Magic Dragon is a featured guest. And the duo will appear on “The Tonight Show Starring Jimmy Fallon” on Friday.

In January, P&T celebrated their 25th anniversary of performing in Las Vegas.

John Katsilometes’ column runs daily in the A section. Contact him at jkatsilometes@reviewjournal.com. Follow @johnnykats on Twitter, @JohnnyKats1 on Instagram.