Jamie-Lynn Sigler I've Had M.S. Since 'Sopranos'

1/20/2016 6:37 AM PST BY TMZ STAFF

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Jamie-Lynn Sigler's been battling multiple sclerosis for more than a decade, but says she's only now ready to go public.

The former 'Sopranos' star said she actually got the diagnosis when she was 19 ... smack in the middle of the hit HBO show's run. 

Sigler says the degenerative disease prevents her from exercising too much. She told People, "I can't walk for a long period of time without resting. I cannot run. No superhero roles for me. When I walk, I have to think about every single step, which is annoying and frustrating."