Jamie-Lynn Sigler revealed she had been battling MS for 15 years to PEOPLE this month

Credit: Andrew Southam

Jamie-Lynn Sigler kept her multiple sclerosis diagnosis a secret for 15 years partly because she was afraid it would affect her career.

The Sopranos star – who was diagnosed with the disease at 20 years old while shooting the fourth season of the hit HBO show – gave her first live interview Wednesday on the Today show since revealing her diagnosis to PEOPLE this month.

When asked by Matt Lauer if she was worried the diagnosis would impact her career, Sigler, 34, admitted, “Yes, very much.”

“One of the first people I told was an industry professional, and I know they were looking out for me at the time but they said: ‘Pretend you didn’t tell me that, and I don’t think you should ever tell anyone that you have this disease. Because people will limit you, people will judge you and they won’t hire you,’ ” Sigler recalled. “And I took that advice. I was 20 years old, I was scared and I thought that was the best thing.”

She did eventually tell some of her cast members, who kept the information private: “Them and my friends and my family, they have fiercely protected me over these years and they wanted me to come out. I just wasn’t ready, I was afraid, but I’m not anymore,” she said.

Now, Sigler said she feels “relief.”

“You know, I lived with this secret that caused me to have so many feelings of shame and guilt and fear for so many years and so I think to finally sort of feel like I’m claiming my power back and being confident with the person that I am, I feel a great weight off my shoulders,” she said.

As for why she felt ashamed, Sigler said that was par for the course when keeping such a big secret for so many years.

“It sounds crazy but when you hold a secret those feelings just come along with that, especially when you hold a secret as long as I did,” she said. “And you know, with something like MS, you lose control over things that you once had and it’s slowly taken away from you and that could chip away at your self-worth and you can feel less-than and a lot of negative feelings and you know, you have to ask for help sometimes – which is something I’m not good at doing, but you have to be able to reach out and when you have a good support system like I have I think it helps a lot.”

Meanwhile, the star doesn’t plan on letting her revelation get in the way any future job opportunities.

“I’m excited about the future. I’m excited to go back to work without feeling that I have something to hide, I feel like I’ll be a better actress for it now that I can show up and really be me,” she said. “I understand that some people may not want to hire me and some people may and I’m open to it but I have every intention of continuing my career.”