The Sopranos actress opened up about the health struggle she has been fighting for almost 15 years in a candid People magazine interview, revealing she was diagnosed with the illness, which affects the nervous system, when she was 20 years old - a year after she was diagnosed with Lyme disease.

In the article, released on Wednesday (20Jan16), Jamie-Lynn credits her new husband, professional baseball player Cutter Dykstra, and their two-year-old son Beau with inspiring her to finally speak out.

"I think I'm at a point in my life with my son, with my new marriage, it's a new me and I want to live my truth," she said. "I don't want to hold a secret where it feels like I have something to be ashamed of or have something to hide... It's part of who I am, but it's not who I am..."

Following her big reveal, the 34-year-old took to social media and told fans, "Thank you People. This is a hard but liberating day for me, and I hope together we can help others and fight on."

Lance Bass, who officiated Jamie-Lynn's weekend (16Jan16) wedding in Palm Springs, California, also took to Twitter to celebrate his best friend's bravery.

"So so proud of my girl!!," Lance exclaimed, before sharing a link to the National Multiple Sclerosis Society's website and urging fans to read up about the condition themselves.

"I couldn't be more proud of my friend," the former 'N Sync star's husband, Michael Turchin, tweeted. "She inspires me every day."

Other celebrity pals also showed their support for Jamie-Lynn.

"Well @JamieLSigler you are a warrior, a strong, beautiful, tough a** lady and momma," Hilary Duff posted, while her sister Haylie added, "So proud of @JamieLSigler shes (sic) brave & a truly beautiful heart. She's setting such a fab (fabulous) example 4 (sic) girls everywhere."

And actress Marla Sokoloff wrote, "Chills reading your story @JamieLSigler - you are a brave and beautiful mama and making a huge impact for many suffering from this disease."