The romance rumors - which also hounded the actors through out their promotional tour for A Star Is Born and the subsequent awards season - reached fever pitch during the 91st Annual Academy Awards when the pair pulled off a steamy duet of their Oscar-winning song "Shallow".
"That's really good. I love that", says Ally to Jack before pushing a strand of hair out of his face and then harmonizing with her musician boyfriend.
Prior to receiving eight Oscar nominations in January, A Star Is Born reaped positive critical reviews on the festival circuit, with Cooper's performance as well as Gaga's first leading role in a major movie earning particular praise from critics.
Gaga added they both had worked on the performance all week, and Cooper as director made decisions like making sure the audience was lit throughout the song, among other details that helped with the illusion of love.
Gaga said she and Cooper worked all week on their performance and she relinquished control of directing it to him. "He laid it all out". "It caused this big controversy because - you had such a connection with Bradley that instantly, and I guess this is a compliment, people started saying, 'Oh, they must be dating..."
Gaga described rooting for Cooper, who ditched the gruff, Sam Elliott-inspired voice of his A Star Is Born character during the stripped-down performance.
It was a HOT performance-especially considering Cooper's longtime girlfriend, Irina Shayk was sitting front and center.
Now, it remains to be seen when we'll see this new cut of the film in the United Kingdom - its U.S. release is imminent, hitting 1,150 cinemas Stateside on Friday for a one-week run.
"Look, I've had my arms wrapped around Tony Bennett for three years touring the world", she said. They must be in love, " Kimmel said.
This past Sunday, Gaga followed in the tradition of Barbra Streisand, who won the best song Oscar but not best actress for her version of A Star Is Born. "And people saw love, and guess what? He said, 'Let's just drop a little bit of joy.' And I said, 'Okay'".
With that as her starting point, Gaga went on to explain that people saw exactly what she and Cooper wanted them to see.
"Sometimes no one would be coming in the restaurant, and I'd be standing there with nothing to do", she continued.
Another asked: "Why do you feel this way about her?"