It's pretty safe to assume that Monday (October 27) is the day that everyone became a Swiftie. But long before Taylor Swift released her album 1989, BFF Selena Gomez has always been there.

Selena just couldn't contain her excitement for her friend's fifth album, posting four oh-so-adorable pictures of them on Instagram, writing that she was "drowning in my bed sheets" listening to 1989.

Related: 7 Reasons Why Selena Gomez Should Move In With Taylor Swift In NYC.

"From hotel room album listening parties, kitchen dance floor album listening parties to driving on the pch, windows down album listening parties. -The best part is we were the only ones there. Each time. So happy, honored and proud to know you and your diaries. @taylorswift #1989 BUY IT!!! -now I'll listen live from drowning in my bed sheets," she captioned the picture.

Taylor obviously loved Selena's pic, tweeting that it "made my day."

I want to be BFFs with these girls so bad.

Selena wasn't Taylor's only friend to show some serious love for her on album release day. Lorde tweeted that she was "so proud of my sista," while Lena Dunham declared "every single song" her favorite (I have to agree).