The Pretty Little Liars star, 21, revealed on Tuesday’s episode that after gaining nearly 70 pounds over two years due to a hormone condition called Polycystic Ovary Syndrome, she’s lost 15 pounds.
“I’m feeling like me again,” Pieterse told viewers. “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.”
PEOPLE’s special issue 25 Seasons of ‘Dancing with the Stars’ is on stands now.
The actress said she received some nasty comments after she started to gain weight. “It was really, really hurtful the way people reacted,” the star revealed. “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.”
On top of that, Pieterse didn’t know why she was seeing numbers rise on the scale.
RELATED VIDEO: Dancing Pro Mark Ballas Teases His Upcoming ‘DWTS’ Partner in Three Words
“I had no idea what was going on and I didn’t have any way of solving it,” she explained. “Very recently I was diagnosed with PCOS, Polycystic Ovary Syndrome, [a] hormone imbalance. And finally I knew why this was happening to me.”
After dancing with partner Gleb Savchenko to Hailee Steinfeld’s “Most Girls,” Pieterse continued to glow.
“I feel like I’ve always been a happy person, and I’ve been so blessed with and amazing family and friends,” she told cohost Erin Andrews. “But I don’t know, I went through a hard time, so feeling like me again, it means the world honestly.”
Pieterse told PEOPLE after the show that she’d been exercising “like crazy” and eating healthy prior to joining DWTS, but the competition allowed her to double down on her efforts — and have a platform to safely open up about her illness.
“Having Gleb and everyone at Dancing With the Stars be so supportive of me and having that outlet means a lot,” she said. “The fact that I can open up and share this with people and hopefully bring awareness to PCOS is really all I can ask for.”
The South Africa native went on to explain 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,” Pieterse, who will return to Freeform for a Pretty Little Liars spinoff, continued. “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.”
Dancing With the Stars airs Mondays on ABC at 8 p.m ET.