United Kingdom, April 13 -- No Doubt star Tom Dumont has been diagnosed with early-onset Parkinson's disease.

The 58-year-old guitarist - who joined the band in 1988 - revealed he started experiencing symptoms "a number of years ago" and admitted it's been a "struggle every day" but he's currently "doing well" and is still able to play music.

In a video posted on Instagram, he explained he's been getting ready for No Doubt's upcoming residency at the Sphere in Las Vegas and he wanted to share his health news with fans. Tom said: "The last couple of months getting ready for the No Doubt Sphere shows, it's been very fun, looking through old footage and looking at old photographs and relearning old songs ... It's kinda made me think about ...