Work: Lady Gaga was spotted radiating throwback chic as she emerged from Radio City Music Hall this Thursday night

Gaga slipped into a multicolored gown that shimmered with sequins and featured a plunging neckline to show off plenty of cleavage.

Meanwhile Tony, true to form, was dressed in a black tuxedo with black tie and a blue pocket square redolent of the first area of his stardom.

As he exited Radio City Music Hall with his wife he could be spotted stopping to graciously sign autographs for fans.

Gaga and Tony, who released a whole duets album called Cheek To Cheek together in 2014, set just two dates for their current engagement.

End of the road: The 35-year-old singing sensation had just wrapped up the final show of her concert series with her longtime collaborator Tony Bennett

The booking was a farewell outing for their collaboration and was entitled One Last Time, with shows on Tuesday and Thursday of this week.

Gaga, who has another duets album with Tony called Love For Sale coming out October 1, was effusive about him onstage during Tuesday’s show.

The evening happened to be Tony’s birthday so she altered the lines of Kander & Ebb’s song New York, New York to fit the occasion.

‘Start spreading the news, it’s Tony Bennett’s birthday,’ she sang according to a review of the show in USA Today.

Details: Gaga and Tony, who released a whole duets album called Cheek To Cheek together in 2014, set just two dates for their current engagement

Gaga, whose Christian name is Stefani Germanotta, gushed: ‘He’s my friend. He’s my musical companion. He’s the greatest singer in the whole world.’

She led a round of applause for him after he sang his signature tune I Left My Heart In San Francisco to close Tuesday’s show.

The venue was sold-out and Tony sang solo for a half an hour, receiving multiple standing ovations as he worked through the set.

Tony’s Alzheimer’s was confirmed in an AARP Magazine profile where Susan shared that he occasionally becomes unaware of where he is.

Side by side: Tony, 95, whose Alzheimer’s diagnosis went public in February, was also seen leaving the famed concert venue on the arm of his wife Susan Crow, 54

Swank: Meanwhile Tony, true to form, was dressed in a black tuxedo with black tie and a blue pocket square redolent of the first area of his stardom

While he recorded his upcoming second duet album with Lady Gaga between 2018 and 2020 his condition was evident, Susan said.

In the profile it emerged that Susan also ensures he gets a workout three times a week because the illness’ effects can be ameliorated by good blood flow.

She also serves him a Mediterranean diet which is said to be helpful for those suffering from the degenerative condition.

Fan service: As he exited Radio City Music Hall with his wife he could be spotted stopping to graciously sign autographs for fans

Gaga’s collaboration with Tony began in 2011 when they sang the Rodgers And Hart classic The Lady Is A Tramp together for his album Duets II.

‘The fact that Tony sees me as a natural-born jazz singer is still something that I haven’t gotten over,’ she said in his AARP Magazine profile this year.

Cheek To Cheek followed in 2014 and then the year after the album came out they went on tour in support of it through North America and Europe.

Big day: This Tuesday, the first night of his Radio City concert engagement with Lady Gaga, also happened to be Tony’s 95th birthday

Susan made the decision to disclose Tony’s Alzheimer’s disease in conjunction with the singing star’s eldest son Danny from a previous marriage.

During the AARP profile Susan revealed that Tony was so far gone that they had to elect to reveal his Alzheimer’s without consulting him.

Danny said he ran the decision by Gaga ‘because she watches his back all the time. She was like: “Absolutely, it’s just another gift that he can give to the world.”‘