Simone Biles and Jordan Chiles have proven to be a dynamic duo at the Tokyo Olympics.

Biles emphasized their friendship in a caption to a picture she shared on Instagram on Tuesday.

“that’s my bestfriend, she a real bad b ????,” the Olympian wrote on Instagram.

Chiles, who previously was going to quit gymnastics after feeling uncertain about her future in the sport, said her teammate was the catalyst in motivating her to keep going.

"I felt like I was a nobody and no one knew who I was. I started questioning, 'Do I even need to be doing this sport?'" the 20-year-old told ESPN. “After [national] championships, I didn't want to do it anymore. I thought about quitting elite and dropping down to level 10 and then going to college and enjoying my college career. But my family was like, 'No, you can do this' and Simone was so supportive and so encouraging. And to get that from her, this amazing Olympic athlete, I was so honored and it was a big help to get me through."

Biles has also mentioned how “inspiring” it has been to watch Chiles grow since the two were assigned as roommates at the World Championships Centre (WCC) in 2018.  

"Jordan has improved significantly since she first arrived at WCC, both mentally and physically," the 24-year-old said. "It's been exciting to watch her grow in and out of the gym. I see her pushing herself every day, which is inspiring. She's sacrificed so much for her dreams."

In 2018, Chiles placed 11th in the all-around competition at the U.S. Championships, leading to feelings of inadequacy and frustration. Biles stepped in and invited the gymnast to train with her at her gym in Texas, which was much less strict than Chiles’ old facility, Naydenov Gymnastics, in her hometown of Vancouver, Washington.

Ultimately, she left Washington behind and began anew in Texas.

"I discovered that gymnastics doesn't always have to be about strictness and being so hard on yourself and having so much doubt," Chiles told The New York Times. "I actually realized this when I saw Simone compete. She looks like she's having fun out there, laughing and giggling, and doesn't look stressed or tired. I was like, 'You know, I'm going to try that one of these days and see how it turns out.'"

Chiles says packing up and moving to Texas was one of the best decisions she’s ever made. 

"The experience of [training with Biles] in the gym and being her teammate definitely is a game-changer," Chiles said. "I never had a teammate before this and when I went there, I was like, 'Whoa, this is what it is like to have teammates? This is cool."

"It's a different type of energy than you see in most gyms. We all laugh, we tell jokes, we give each other hugs and high fives and fist bumps and it gets us through the tough days. We all want to push each other to do our absolute best," she added.

“To my best friend, just thinking about everything we have gone through together from us getting mad at each other for no reason to laughing at jokes, to bringing the love of this sport back to me with your help words can’t explain how proud I am of you,” Chiles wrote in an Instagram post. "I LOVE YOU and am literally crying just thinking about everything. WE did this together????  -love jo????????????."