Taylor Swift's selfie with Selena Gomez and Cazzie David sends Twitter into a tizzy

Taylor Swift and Selena Gomez are hanging out again -- with an unexpected guest!

The powerhouse duo, whose years-long friendship has long been the subject of speculation ("Are they still friends?" is a common question posed on social media), spent time together this week, and the social media evidence of their girls' night in has fans in a tizzy.

Swift took to Instagram on Thursday night to share a blurry selfie with Gomez and Cazzie David, the daughter of comedian Larry David who had famously been dating Pete Davidson just weeks before he got engaged to Ariana Grande last spring.

"20wineteen," Swift captioned the photo, which shows her holding an almost-empty wine glass with a bit of white wine in it. Gomez is holding a mug, which implies that she was not joining in on the night's drinking.

Of course, the photo quickly went viral for a multitude of reasons: First, it was a friendship that nobody really knew about. Second, Gomez has been completely silent on social media since entering rehab last year to receive mental health treatment and has only just begun to be seen out and about in public. And, third, anytime that Gomez and Swift hang out, it proves to any naysayers that, yes, they're genuinely still pals.

Needless to say, fans had a lot to say about the selfie.

"brb calling the met to ask which part of the museum this tipsy insta of taylor swift cazzie david and selena gomez will hang in," one person tweeted.

"Cazzie David (the woman on the left) is a writer at vogue," someone else noted of David's side-hustle. "WHO KNOWS maybe we will get an interview with Selena and Taylor both? Or they were just simply hanging out?"

Others wondered what Swift and David's newfound friendship means for a potential Swift/Grande duet in the future.

"So if taylor is with cazzie david do u think she could still collab with ariana," one user mused.

David also shared a photo from the girls' night. On her own Instagram, the comedian shared a snap of a polaroid that showed her cuddling with Swift and Este Haim, one of Swift's longtime friends who is in the band HAIM.

"Had a meet and greet for my fans last night," she captioned the photo. "I love u all."

The caption confirmed the timing of their hangout, which some thought explained some of Swift's unusual social media activity this week.

Other longtime fans used the photos as evidence of Swift and Gomez's enduring friendship, despite constant speculation and third-party factors that have threatened to come between them.

"I think its so amazing that taylor and selena met when they were 16/17 and they've been best friends and have always supported each other despite what the media or anyone says," a fan wrote. "They always stick together and i think thats wonderful and we all deserve a friendship just like taylena."