Tony Bennett has hailed Lady Gaga as the "ultimate entertainer" after he was left in complete awe following one of her recent Las Vegas residency shows.

The crooner teamed up with Gaga for a joint standards album, titled Cheek to Cheek, back in 2014, and they hit the road together to promote the project in 2015.

Bennett has remained close to the pop superstar ever since, and last year (19), reunited with Gaga onstage for the launch of her Jazz & Piano concert residency in Las Vegas.

He recently returned to Sin City to see his pal perform once more, this time choosing to remain in the crowd, and Bennett admits it's always a thrill to watch the Grammy and Oscar winner at work, because she can command the stage like no other.

The veteran singer shared his admiration for the Born This Way hitmaker in a question and answer session with Twitter fans on Thursday (26Mar20), after he was asked to name his favourite performance viewed as an audience member.

"Most recently was seeing Lady Gaga's Jazz and Piano show in Vegas," he replied. "She's ultimate entertainer and the audience enthralled the whole time (sic). You can learn how to perform but entertaining an audience is something else. She has it all."

And Bennett wouldn't hesitate to collaborate with Gaga once more if the opportunity arose.

"I love working with 'Lady' so anytime she wants to sing live or in the studio I am always ready," the 93 year old shared.

"She is an incredible artist and a wonderful person. We had such a great fun touring together - she gives her all to the audience (sic)."

Bennett will have to wait if he wants to join Gaga onstage again as her Vegas gigs - like the majority of live shows - have been put on hold until the coronavirus pandemic passes.