Michael Phelps knows the pressure of being in the Olympics, which is why he understands what Simone Biles is feeling after she withdrew from USA Gymnastics' team final competition on Tuesday.

Biles left the competition following an awkward landing during her vault exercise. It was thought she suffered a physical injury when the team announced she had a “medical issue.” The 24-year-old, however, later clarified that she's physically healthy but suffering from mental health problems amid the pressure and the spotlight that was put on her.

“Physically, I feel good, I’m in shape,” Biles told Hoda Kotb on TODAY. “Emotionally, that kind of varies on the time and moment. Coming to the Olympics and being head star isn’t an easy feat, so we’re just trying to take it one day at a time and we’ll see.”

After learning about what happened to Simone Biles in the Tokyo Olympics, Michael Phelps showed his support to his fellow Olympian. He also shared the struggles that all athletes like him have to endure before sending a compassionate message to the American gymnast.

Phelps also shared her admiration for Biles for opening up and asking help when she needed it.

“We're human beings. Nobody is perfect. It's OK to not be OK. It's OK to go through ups and down and emotional rollercoasters. The biggest thing is, we all need to ask for help when we go through those times. … It was hard for me to ask for help,” Phelps said on NBC, per Nicole Auerbach of The Athletic.

A lot of athletes, celebrities and fans supported Biles in her decision for the Tokyo Olympics competition. Aside from her former teammates in Aly Raisman and Laurie Hernandez, Boston Celtics star Jayson Tatum came into the defense of the young gymnast after Charlie Kirk called her a “selfish sociopath” and a “shame” for USA.

It's certainly great to see athletes coming together in support of another. As Phelps said it, it's not easy–let alone opening up that they need help.