Taylor Swift's Birthday Message To Este Haim Proves She's Totally Part Of The Family — VIDEO

It's no secret that Taylor Swift is practically the fourth member of the band Haim. She hangs out with the three sisters so much that she's basically become part of the family. For that reason, it makes perfect sense that Taylor Swift shared a super sweet birthday message to Este Haim (the oldest of the sisters) on Saturday afternoon.

In typical Swift fashion, she won "best birthday wish," if there was actually a ranking system for these kinds of things. It's unsurprising, since a few weeks ago Taylor Swift threw an awesome birthday party for Camila Cabello of Fifth Harmony. Tay is like that friend who makes everyone feel like a princess on their big day, because she genuinely cares. If this was middle school, she'd be the one to decorate a friend's locker with an excessive amount of balloons and streamers.

Nowadays, a sincere b-day Instagram post is the equivalent of a decorated locker. In the video, Swift and the Haim sisters are singing in the car to Faith Hill's catchy 1998 classic "This Kiss." Using a Gatorade bottle as a microphone (because of course), the girls belt out the lyrics. It looks like the most fun road trip of all time. Swift captioned the post:

Happy Birthday, Este!! Ever since you, Alana, and Danielle adopted me into your wolf pack, life has never been the same. @haimtheband

They really have adopted Swift as part of their pack. The foursome is inseparable. From the hanging out at the beach (where T. Swift finally revealed she has a belly button) to window-shopping with Papa Swift, they spend tons of time together.

After Swift tweeted out the video, Faith Hill gave her seal of approval.

See the video for yourself below! Just a warning, the song may get stuck in your head for the rest of the day:

Swift wasn't the only one to send Este some birthday love. The other Haim sisters posted equally great throwbacks on Instagram.