Tony Bennett and Lady Gaga have headlined in Las Vegas, including dates at Chelsea at the Cosmopolitan of Las Vegas on Dec. 30-31 2014 when they kicked off their international “Cheek To Cheek” tour.

Tony Bennett & Lady Gaga perform at The Axis at Planet Hollywood Resort & Casino in Las Vegas, NV on April 10, 2015. (Courtesy, Erik Kabik)

Tony Bennett and Lady Gaga perform together at The Chelsea in The Cosmopolitan of Las Vegas, Tuesday, Dec. 30, 2014. (Ethan Miller/WireImage)

Lady Gaga and Tony Bennett brought their "Cheek to Cheek" album to PBS for "Great Performances" last summer (Courtesy PBS)

Lady Gaga and Tony Bennett, the historic, generations-spanning duo, are reunited on the Strip this weekend.

Bennett is in town to take in Gaga’s shows tonight and Sunday night at the Park Theater. Word is he originally had planned to surprise Gaga by showing up unannounced Sunday. Instead, he checked into The Signature at MGM Grand and informed Gaga of plans to be at the show tonight and again Sunday night.

Bennett’s appearance at that second show Sunday is particularly tantalizing. That showcase is the opening of Gaga’s “Jazz & Piano” series, music-centered show with a big band that is to include several Las Vegas musicians.

Bennett and Gaga, of course, have headlined in Las Vegas, including dates at The Chelsea at The Cosmopolitan of Las Vegas on Dec. 30-31, 2014, when they kicked off their international “Cheek To Cheek” tour.

They also appeared the following spring at then-Axis Theater (now Zappos Theater) at Planet Hollywood, with such classics as “Smile,” “Luck Be a Lady” and “I Left My Heart in San Francisco” in the set list, which was also dotted with Gaga’s hits.

The “Cheek To Cheek” album was released September 2014.

Gaga’s “Enigma” residency also features nine throwback “Jazz & Piano” shows. We can expect a mic is open and ready for Mr. Bennett.

John Katsilometes’ column runs daily in the A section. His PodKats podcast can be found at reviewjournal.com/podcasts. Contact him at jkatsilometes@reviewjournal.com. Follow @johnnykats on Twitter, @JohnnyKats1 on Instagram.