Saved By The Bell star Dustin Diamond has been diagnosed with cancer and is receiving treatment in hospital, his team have confirmed.
The 44-year-old actor, who is best known for his role of Screech in the 90s US sitcom, is understood to have fallen ill last week.
A post on his official Facebook page read: "At this time we can confirm that Dustin does have cancer. Dustin will disclose more information once it is available and a plan moving forward is made."
They also supplied an address for fans to send cards and letters, adding that "positivity and prayers are appreciated".
Diamond's agent, Roger Paul, also confirmed his diagnosis, and told the PA news agency: "We will know the severity of it when the tests are done."
He says he expects an update next week.
Celebrity website TMZ said the actor had first discovered a lump in his throat, leading to the diagnosis.
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Diamond played nerdy sidekick Samuel 'Screech' Powers in the original Saved By The Bell across four seasons, from 1989 to 1993.
He also appeared in 1992 TV movie Saved By The Bell: Hawaiian Style, and revivals The New Class and The College Years.
However, Diamond did not appear in the most recent 2020 revival series which starred several of the show's original stars.
Following his early TV fame, the actor controversially released a self-directed sex tape in 2006.
In 2009 he wrote a tell-all book about his time in the teen sitcom, later saying many of the salacious details were exaggerated by his ghost-writer.
Diamond later appeared on the UK's 12th series of Celebrity Big Brother but was evicted in the third week.
In 2015 he spent three months in jail after being convicted of disorderly conduct and carrying a concealed weapon following a bar fight in Wisconsin.