Selena Gomez gave her first big interview of 2020 to WSJ magazine ahead of Rare‘s release on Friday, and the outlet got Taylor Swift to speak about Gomez and their 13-year friendship, too.

Their quotes reveal just how deep their bond goes and how intimately Swift understands what Gomez went through behind the scenes with her Justin Bieber heartbreak, struggles with lupus, and her mental health issues (Gomez told WSJ she has been working with therapists for six years: “I realized that there was a way to get help and to find people that you trust. I got on the right medication, and my life has been completely changed”).

The two became close when they were both dating Jonas Brothers—Swift with Joe Jonas and Gomez with Nick Jonas. “We clicked instantly and, man, that was my girl,” Gomez said.

“There has always been this quality of sisterhood, and I don’t say that in a basic way,” Swift added. “I knew from when I met her I would always have her back. In my life, I have the ability to forgive people who have hurt me. But I don’t know if I can forgive someone who hurts her.” (Taylor Swift made headlines this summer for liking a Tumblr post that called Justin Bieber out for cheating on his ex Gomez amid her Scooter Braun drama, in one public example of this.)

“We both went through sh*t at the same time,” Gomez said. “She taught me a lot about how I should be treated at a young age.”

Gomez explained to WSJ that she and Swift really became close in private. “There’s so much of my friendship with Taylor that people don’t know about because we don’t necessarily feel the need to post about everything we do,” she said. “She has showed up for me in ways that I would have never expected. Flown in because I was hurt and was going through something. Stuff that was going on with my family. It’s been proven year after year and in every moment of my life that she is one of my best friends in the world. We don’t agree on everything, but we respect each other with everything.”