A billion email accounts got hacked, you say? Break out the bubbly!

Yahoo employees filled a bathtub with ice and champagne at a cup-runneth-over office Christmas party Thursday night — despite the fact that the tech giant had just disclosed it was the victim of the biggest cyber-attack in history.

Worker bees under Chief Executive Marissa Mayer snapped photos of each other lounging around the well-stocked tub at a shindig whose theme was “House Party,” freely sharing the pics on social media.

“Hanging by a tub full of champagne,” Instagram user mrsbeeinthecity wrote on her page. “No biggie.”

Another Instagrammer tagged himself “champagne papi,” posting a photo of himself sitting in the ice as he hoisted an uncorked bottle to his lips.

Still, the bash, at an undisclosed location, appeared to be a modest affair compared with last year, when Mayer reportedly shelled out $7 million for a “Great Gatsby”-themed party at Pier 48 in San Francisco.

Indeed, the 2016 bash got staged despite the fact that Verizon might demand a price cut on its planned $4.83 billion purchase of Yahoo — or even ask to scuttle the entire deal on worries that the newly disclosed hack could scare users away from its site.

In 2014, Mayer reportedly spent $70,000 on a photo shoot of the company’s top executive team dressed as characters from “The Wizard of Oz,” with Mayer done up as Dorothy.