We hear a lot about celebrity friendships.

They might not be as juicy as celebrity hookups or relationships — not usually, anyway — but it’s always interesting to see which stars commit to lasting bonds despite busy schedules and feuds and controversies.

Francia Raisa and Selena Gomez

Selena Gomez’s friendship with fellow actress Francia Raisa is clearly strong as hell.

They’re always there for each other. Oh, and Francia gave Selena her kidney.

As she revealed nearly two years ago, Selena Gomez has Lupus.

Lupus is a rare but devastating disease in which a person’s own immune system attacks their healthy cells.

It can be lethal and can cause all sorts of health problems. There are treatments that exist thanks to modern medicine, but there is no cure.

To treat her Lupus, Selena Gomez has undergone multiple chemotherapy treatments.

Selena Gomez Keeps It Simple

Chemo may help with her lupus, but the poisonous doses exact their own hellish toll in the process.

Throughout all of this, we’ve learned that Selena Gomez is a total badass.

As she revealed on Carpool Karaoke with James Corden, Selena Gomez does a shot of ginger every morning.

James Corden did it and it was agonizing. Next to the ravages of Lupus and chemo, what’s a little ginger? Selena just shrugs it off.

(Seriously, inspired by Selena’s example, my roommate tried a shot of ginger and he … will never try that again)

Unfortunately, sometimes even chemo isn’t enough.

You know how Selena hasn’t quite been out and about to promote her music as much as you might expect this summer?

There’s an unfortunate reason for that.

Selena Gomez and Francia Raisa, Kidney Donation

In this photo, which Selena shared early this morning on her Instagram, Francia Raisa holds hands with Selena Gomez in side-by-side hospital beds.

Selena’s caption explains it all:

“I’m very aware some of my fans had noticed I was laying low for part of the summer and questioning why I wasn’t promoting my new music, which I was extremely proud of.”

Yep. Her songs have been all over the radio but she’s been … shy.

“So I found out I needed to get a kidney transplant due to my Lupus and was recovering. It was what I needed to do for my overall health.”

“I honestly look forward to sharing with you, soon, my journey through these past several months as I have always wanted to do with you.”

We can absolutely understand why she’d keep things under wraps.

Selena Gomez Sends Smooches

“Until then I want to publicly thank my family and incredible team of doctors for everything they have done for me prior to and post-surgery.”

Sure.

“And finally, there aren’t words to describe how I can possibly thank my beautiful friend Francia Raisa. She gave me the ultimate gift and sacrifice by donating her kidney to me. I am incredibly blessed. I love you so much sis.”

Seriously — and there’s nothing wrong with what Selena says, here — how do you even begin to express your appreciation for something like this?

It’s a kidney.

You only have two.

“Lupus continues to be very misunderstood but progress is being made. For more information regarding Lupus please go to the Lupus Research Alliance website: www.lupusresearch.org/ -by grace through faith”

As we said, you only have two kidneys.

Selena Gomez: KIIS FM's iHeartRadio Jingle Ball 2015

Giving up one of them is a huge deal. No words, Selena’s our ours, can properly convey how significant this is.

If Selena needed a transplant from her friend Francia, we can only assume that her Lupus had ravaged both of her kidneys to the point where she needed at least one new, healthy one.

That is an incredibly sweet and generous thing for her friend to do.

Even if she and Francia were genetic sisters (though they do refer to each other as “sister,” which is precious), this would be above and beyond.

It is, of course, terrible that Selena needed that procedure in the first place.

(Also, we wish that organ cloning were already an FDA-approved, standard procedure so that one person needing a kidney wouldn’t require two people going under the knife)

Lupus is a terrible disease. We’re just glad that Selena Gomez has the resources to be able to afford all of the necessary treatments.

And, of course, that she has a ride-or-die friend like Francia.