They're all about the #21yearschallenge.

By Christopher Luu
Updated Mar 29, 2019 @ 9:15 pm

Friends who Disney together, stay together. Just take a look at Sarah Michelle Gellar and Selma Blair, who just spent a magical day at Disneyland. It wasn't just a fun outing with the head mouse in charge, however. Gellar used the opportunity to share some sweet throwback picks, instituting her very own challenge, complete with its own hashtag — the #21yearschallenge.

It's not the only hashtag Gellar used. In both of the snapshots, which are side-by-side photos showing past Disneyland trips with this week's adventure, she added #flashbackfriday. In one photo, the two can be seen on Mr. Toad's Wild Ride, an attraction that can probably boast a long line of celeb fans thanks to its position in the pantheon of classic Disneyland rides. Blair and Gellar are even striking a similar pose, so either these photos were planned well in advance or the pals just share a close, enchanting connection.

The second post is another master class in throwback posing. While neither Gellar nor Blair are wearing a pair of ears in the older photo, they look like they're having a great time. They've swapped sides in the snapshot, but the pose is spot-on.

The Disneyland trip is the latest outing for Blair, who's kept a low profile since her multiple sclerosis diagnosis. Before this, she arrived at an Oscars after-party with a cane and a powerful message. Gellar and her husband, Freddie Prinze Jr, were among the very first people to offer words of support after Blair revealed her diagnosis. It's clear with these cheerful photos that she's keeping her support system close. And if these best friend photos keep filling feeds, it's only a matter of time before the Cruel Intentions movie nights happen. Can someone call Reese?