They were so close, everyone thought they would kiss Photo: Reuters.

Lady Gaga and Bradley Cooper sparked yet more rumours about the true nature of their relationship tonight when they gave a very intimate performance together at the Oscars 2019.

Gaga and Bradley gave a steamy performance of their hit single “Shallow” and nobody could take their eyes off the couple as they cosied up next to each other on the piano stool.

Bradley kept gazing at his “A Star Is Born” co-star as she sang lustfully at the piano, wearing a voluminous black gown.

And it didn't take long for him to join her at the piano, even wrapping his arm around her waist delicately as she belted out the last chorus.

Viewers couldn't believe what they were seeing, especially as 44-year-old Bradley had his mum, Gloria Campano, sitting in the audience directly in front of them along with his model partner Irina Shayk.

While the camera didn't linger on Irina's face, fans could only wildly guess at what she must have been thinking watching her partner smile tenderly at Lady Gaga.

"Someone look at me the way Bradley Cooper looks at Gaga at the end of this song," one tweeted.

Bradley didn't take his arm off her until well after their performance finished.

"Everyone looking at Bradley Cooper’s girlfriend while him and Gaga set a fire on stage," quipped another.

A third wrote: "I feel so bad for Bradley’s girlfriend him and Gaga look like they about to kiss 24/7."

While another joked: "I can’t believe we all just witnessed Lady Gaga getting pregnant."

Gaga even told Bradley she loved him during her acceptance speech for her Original Song award.

"I want to thank my family, my mum, my sister I love you, Bradley," she sobbed on stage.

Gaga with Bradley and Irina.

Earlier in the show, eagle-eyed viewers pointed out that Victoria's Secret model Irina had strategically placed herself between Bradley and Gaga when all the celebrities came in to take their seats.

While you might expect two co-stars to sit together, Irina made sure she was in the middle of the pair, perhaps to keep a watchful eye on their goings on.