During the second week of competition, the Pretty Little Liars alum, 21, revealed she gained nearly 70 lbs. in two years due to a hormone condition called polycystic ovary syndrome (PCOS).
“I’m so thankful to Dancing with the Stars for giving me that platform,” Pieterse said at PEOPLE’s Ones to Watch Party at NeueHouse in Los Angeles on Wednesday.
“I loved that I was able to share that with people and bring awareness to it. The response has been amazing,” said the actress, who wore a dress by Zhivago to the party, which was presented by Maybelline New York.
“It’s all positive and supportive. I’ve actually come into contact with so many friends who have PCOS that I never even knew. This is something that’s really important to me and glad that it’s getting shared.”
The South Africa native previously told PEOPLE about the severity of the disorder.
“There’s a lot of symptoms – like irregular periods, weight gain, impossible to lose weight — that seem somewhat normal sometimes depending on your lifestyle, but I feel like you have to just go and get it checked,” said Pieterse, who will return to Freeform for a Pretty Little Liars spinoff.
“PCOS can lead to ovarian cancer and breast cancer and thyroid issues that could’ve been avoided. More than half of woman have it, and they don’t even know. It really is a huge issue that I want to share and hopefully help even one person deal with it.”
“It was really, really hurtful the way people reacted,” the star told viewers. “People were staying stuff like, ‘She’s pregnant.’ ‘You’re fat.’ They were angry or mad that I looked like this. It was one of the hardest things I have ever been through.”
But thanks to the dancing and exercise of DWTS, she’s lost 15 lbs.
“I’m feeling like me again,” Pieterse said during the episode. “Being on the show, I’ve lost over 15 pounds. It’s not an easy road, but being able to focus on getting myself healthy again, and the fact that I’m seeing results, getting better is all I can ask for.”