The 44-year-old actor was hospitalised in Florida earlier this month and announced that he was diagnosed with cancer.
Mr Diamond’s team provided an update on his condition, telling TMZ that he is battling “stage 4 small cell carcinoma”, commonly known as advanced lung cancer.
According to TMZ’s report, the cancer started elsewhere in his body and metastasized in his lungs. His next round of chemotherapy is “being scheduled soon”.
Following his first round of chemotherapy, representative Roger Paul said the former child-star is “looking forward to spending more time with his girlfriend, playing his bass guitar/video games” and “making videos for his fans on social media."
Mr Paul added that those wishing to support Mr Diamond during this time can send the actor mail.
"We are forwarding the letters/cards to him to read in the hospital," he said.
Dustin's former co-star Mario Lopez , who played A.C Slater in the American sitcom, shared his support for the actor after news of his diagnosis broke.
Sharing an image of the two on Instagram, Mr Lopez wrote: "I connected with Dustin earlier this evening and although the news of his diagnosis is heartbreaking, we remain positive that he’ll overcome this. Praying for him & his family and for a speedy recovery. God Bless."
Tiffani Thiessen, who starred as Kelly Morris, Elizabeth Berkley, who played Jessie Spano, and Lark Voorhies, who took on the role as Lisa Turtle, also took to social media to send their support to their former colleague.
“I’d like to take the time to send special love and special best wishes to Dustin Diamond, who is one of my dearest friends," Ms Voorhies wrote on Instagram, alongside an image of the stars.
“Dustin, all the many in your close circle who know you to be the great person that you are, are truly pulling for you and praying for the best outcome.”
Mr Diamond's hospitalisation comes as the reboot of Saved By the Bell was renewed for a second season on NBCUniversal's streaming service, Peacock.
“I’m thrilled that Saved By the Bell has been renewed. I’ve been blown away by all the love for the show and can’t wait to go back and make more episodes,” said writer and executive producer Tracey Wigfield.
“Hopefully we stay on Peacock for many more seasons, and then in 30 years, somebody does a reboot of our reboot and invents the threeboot.”
The show is currently no.1 on the streaming service and stars original cast members Berkley, Lopez, Thiessen and Voorhies, as well as Mark-Paul Gosselaar.