Selena Gomez's BFF Francia Raisa Reveals Why She Decided to Give Her a Kidney

Selena Gomez and Francia Raisa are ready to talk — together.

The “Wolves” singer, 25, shocked fans in September by announcing that, due to lupus complications, she’d received a kidney transplant from her best friend Raisa over the summer. The two pals sat down with Today for a joint interview about the surgery, recovery and the months since.

“My kidneys were just done,” Gomez told Savannah Guthrie. “That was it, and I didn’t want to ask a single person in my life. The thought of asking someone to do that was really difficult for me. She volunteered and did it. And let alone someone 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 was sharing a house with Gomez when she realized how weak her friend was becoming.

“One day she came home and she was emotional. I hadn’t asked anything. I knew she hadn’t been feeling well,” the Grown-ish actress said. “She couldn’t open a water bottle one day. She chucked it and she 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.

She continued, “It just vomited out of me: I was like, ‘Of course I’ll get tested.’”

Raisa explained that because they were in an “emergency situation,” she completed her testing in a day — a process that usually takes about six months.

Before the surgery day, the girls had a friend French braid their hair and ate a big meal. But the fear was certainly there.

“I had to write a will, which was scary because there’s no guarantee I’ll wake up,” Raisa said.

Raisa went into surgery first and everything went well. Gomez also woke up from her procedure feeling fine but realized an excruciating pain as she tried to nap.

Doctors told Gomez that she would have to go back into surgery, as her new kidney was turning around inside her body.

“My teeth were like grinding, I was freaking out,” Gomez explained. “It was a six hour surgery that they had to do on me, and the normal kidney process is actually two hours.”

She added, “Apparently one of the arteries had flipped. I’m very grateful that there are people who know what to do in that situation.”

The recovery process was tough. The women were unable to do anything, from putting on underwear to taking a shower, without assistance. Gomez also said that they were on bed rest and only allowed to walk for an hour each day.

Gomez has been open about her battle with lupus for several years, and first revealed in 2015 that she’d undergone chemotherapy to treat the disease. Lupus causes the immune system to attack its own organs and tissues and can affect the whole body. According to the Lupus Foundation of America, about half of all cases of systemic lupus affect a major organ such as the heart, lung, kidneys or brain. In some cases, it can take years for the disease to be diagnosed and properly treated.

Last month PEOPLE spoke with a doctor who specializes in transplants for people with immune diseases including lupus, Robert Montgomery, MD, director of the Transplant Institute at NYU Langone Health. Dr. Montgomery told PEOPLE that it’s common for lupus to damage kidneys to the point where one or both need to be replaced. “Not every patient who gets lupus ends up with kidney failure, but some do,” he said.

When lupus patients need organ donations they are often added to a waiting list to be matched with a deceased donor, and they may have to go on dialysis for kidney failure while they wait months or even years. In Gomez’s case, she had Raisa to serve as her live donor, which Dr. Montgomery said is a “great advantage” because “live donor transplants last twice as long, on average, as deceased donor kidneys.”

Raisa said the experience brought them even closer. “I am beyond grateful that God would trust me with something that not only saved a life, but changed mine in the process,” she said.

Watch the Today show interview here.