Over the summer, Selena Gomez underwent a life-saving kidney transplant as a part of treatment for her Lupus diagnosis. The singer first revealed last month on Instagram that she underwent the procedure, and spotlighted her friend and fellow actress Francia Raisa, who donated a kidney to her.

In a new sit-down interview with Savannah Guthrie on the Today Show, the pair publicly open up about their medical experience for the first time together. Here are some of the most revealing parts of their discussion.

Selena was suffering from kidney failure, arthritis and other serious symptoms from Lupus before the surgery.

"I had arthritis, my kidneys were shutting down, my mentality was just to keep going," Gomez said. "I didn't realize how much of it was affecting my body."

Raisa, who was living with Gomez at the time, found out about the state of Selena's health when she was too weak to open a water bottle. That's when she immediately volunteered to get tested to donate.

"One day she came home and she was emotional," Raisa said. "I hadn't asked anything, I knew that she hadn't been feeling well. She couldn't open a water bottle one day. She chucked it and just started crying and I said, 'What's wrong?' And that's when she told me. And she goes, 'I don't know what to do, the list is seven to ten years long. And it just vomited out of me, I was like, 'Of course I'll get tested.'

Gomez first told Raisa—who's starring in Yara Shahidi's upcoming show, Grown-ish—that there was too much going on in her life for her to be a kidney donor, but she insisted to help out. "I called her assistant and I said, 'Give me the information. I want to do this,'" Raisa added.

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Some of Selena's family members even got tested to donate, but they weren't a match. Francia was.

"She lived with me in this interesting time where my kidneys were just done," Gomez said. "That was it. And I didn't want to ask a single person in my life. The thought of asking somebody to do that was really difficult for me. She volunteered, and did it, and let alone somebody wanting to volunteer, it is incredibly difficult to find a match. The fact that she was a match, I mean, that's unbelievable. That's not real."

Raisa recalled she "did everything in, like, a day," even though the process usually takes six months, because her and Selena's situation was an "emergency situation." The prep included getting her blood and urine tested and going through physical and psychological examinations.

They prepped with a lot of food the night before.

"I wanted us to feel good," Selena explained. A friend came over and french braided their hair. Since they had to fast starting midnight before the surgery, they "stuffed our faces" the night before. "I think I ordered way too much food," Gomez said laughing.

Raisa even had to write a will before donating a kidney.

Her procedure came first that day. "When I woke up, I just was really calm," Raisa recalled. But she had to take extra precautions incase the surgery was unsuccessful. "I had to write a will, which is scary because there's no guarantee you'll wake up."

Her family was also uneasy about her decision to be a donor. "When you told your mom, she was like, 'What are you doing?'" Gomez said. "My mom didn't want to be there until I woke up," Raisa added. "She loves Selena and so she was torn."

Francia and Selena saw each other before undergoing their respective surgeries.

"She came in and held my hand, and she was like, 'Are you good?' I was like, 'Yeah. We're doing this,' Raisa said. The actresss got valium to calm down, but she doesn't remember what came after that. Selena reminded her that she did a quick peace sign before going unconscious.

Gomez "felt good" when she woke up from the surgery, but then experienced complications in the recovery room.

"I remember waking up two hours after [the surgery], I saw my mom, I saw my stepdad, and I felt okay. I felt really good. I got to see you [Francia] and tell you I love you. And then I went back to my room and I started to attempt to fall asleep, and in the middle of that process I started hyperventilating and there was so much pain there," Gomez said. The doctors told her she had to go in for another surgery. Her kidney was turning around.

"My teeth were grinding, I was freaking out. It was a six-hour surgery that they had to do on me and the normal kidney process is actually two hours," she said. "Apparently one of the arteries had flipped. I'm very thankful that there are people who know what to do in this situation."

The recovery process was "humbling" and "brutal."

Gomez wanted her and Raisa to be together, so she got a space for them both to recover in. When they were on bedrest, they could only get out of bed and walk for an hour a day, and they weren't allowed to take stairs.

"It was hard because you constantly had to ask for help," Raisa said. "I think one of the most humbling experiences was needing help to, like, put on underwear. We couldn't take showers by ourselves. It was a really brutal process."

Now that Gomez has a new kidney, there's only a three to five percent chance that her Lupus will come back.

Raisa saved her life, Gomez said. "I guess I got to the point where it was really kind of life or death," she added. "It's really hard to think about or even to swallow, especially now that as soon as I got the kidney transplant, my arthritis went away, my lupus is at a three to five percent that it'll ever come back, my blood pressure, my energy, my life has been better."

The pair hopes that their experience will inspire others.

"I just really hope that we can help somebody," Gomez said tearfully. "I really do. I don't think what we went through is easy. I don't think it was fun. I hope that this inspires people to feel good, to know that there is really good people in the world."

From: AR Revista