Going by the crowd reaction, you've got to imagine that a possible tour has been floated for Bradley Cooper and Lady Gaga.
The singer then took a seat at the piano and began playing as Cooper stood up and leaned over the instrument, joining her in singing the chorus.
The 44-year-old actor, who starred alongside Gaga in the critically acclaimed movie A Star Is Born, joined the chart-topping singer for her show in Sin City, where they performed a rendition of the song Shallow, which features in the film. After Cooper joined her on stage he joked that he couldn't "hear anything" and has "never used" in-ears before.
Three Airports Ground to Halt
Florida's International Airport is also facing the same staff shortage, and flights are being delayed and cancelled there as well. Control towers and centers were understaffed before the shutdown , he said, and the shutdown is only making matters worse.
In video clips shared on social media from concert-goers, Gaga sits at the piano while Cooper is on a stool as they sing the Oscar-nominated track together.
Another person who was in the audience wrote on Twitter: "I think I just had a heart attack" before posting a picture of Cooper, Gaga and the other performers taking a bow.
The crowd reportedly cheered as Cooper made his way to the stage.