The pair held each other in a loving embrace for several minutes, kissing, hugging, smiling and conversing with one another off to the side of the room, and made no attempt to hide their PDA from people in the packed-out venue.
According to the Las Vegas Review-Journal, the couple "canoodled in full view of the crowd with a dark-haired, bearded man known only as Michael as the (first) countdown turned the calendar to 2020".
Gaga – wearing a sparkly gold number and sporting soft pink tresses to welcome in 2020 – was later seen leaving the venue hand in hand with her guy.
"The two acted in a way consistent with an ongoing romance," wrote the paper's journo, who watched the display unfold.
The amorous display seems to fly in the face of recent speculation that a reunion could be on the cards for Gaga and her ex-fiancé Christian Carino, supporting reports that the friendly exes are just that: friends.
“Lady Gaga is talking to Christian again, but as friends,” a source told Us Weekly.
“There is nothing going on there.”
After her rep confirmed news of the couple's split in February 2019, a friend shared to WHO at the time: “It just didn’t work out. Relationships sometimes end.”
Last October, the A Star Is Born actress confirmed her split from boyfriend Dan Horton, on Instagram, sharing a photo at her friend Sarah Nicole Tanno bachelorette party with the caption: “An about to be married woman and me, a single lady."
But it looks like the talented multi-hyphenate didn't stay lonely for long!