Tyler, who was best known for playing Gunther -- the Central Perk manager and Rachel Green's admirer -- on the hit '90s sitcom for 10 seasons, died peacefully at his home in Los Angeles on Sunday, his representative Toni Benson said.
He passed away following a battle with prostate cancer, which was first diagnosed in 2018, Benson said. He was 59.
After news broke of his death, Aniston -- who was starred as Rachel -- paid tribute to him with an Instagram post which acknowledged his contribution to the show's success.
"'Friends' would not have been the same without you," she wrote. "Thank you for the laughter you brought to the show and to all of our lives. You will be so missed #JamesMichaelTyler."
Her post included a clip from the 2004 series finale when Gunther finally plucked up the courage to tell Rachel that he loved her as she prepared to leave New York for a new life in Paris.
Rachel let him down gently by saying she would always think of him whenever she saw a man with "hair brighter than the sun" -- making reference to Gunther's iconic bleached blonde look.
Courteney Cox, who played Monica Geller on the show, remembered Tyler as a magnanimous person.
"The size of gratitude you brought into the room and showed every day on set is the size of the gratitude I hold for having known you. Rest In peace James," Cox wrote alongside a picture of him on her Instagram page.
Joey Tribbiani actor Matt Leblanc also shared a heartfelt message, which said: "We had a lot of laughs buddy. You will be missed. RIP my friend."
Lisa Kudrow, best known for portraying quirky masseuse Phoebe Buffay in "Friends," thanked Tyler "for being there for us all."
"James Michael Tyler, we will miss you," she wrote alongside a photo of him on Instagram.
David Schwimmer, who played palaeontologist Ross Geller, thanked Tyler for "playing such a wonderful, unforgettable role" and "for being such a big hearted gentleman and all around mensch off screen."
"You will be missed, buddy," he added in a tribute posted on Instagram.
Friends" co-creators Marta Kauffman and David Crane told CNN in a statement that Tyler was a "genuinely kind, sweet man."
Tyler shared the news of his diagnosis publicly during an appearance on NBC's Today Show in June. He said he had lost his ability to walk after the disease started "mutating," causing tumors up and down his spine.
He made a brief virtual appearance at the "Friends" HBO Max reunion earlier this year.
"It was the most memorable 10 years of my life, honestly," the actor said during the TV special.
"I could not have imagined just a better experience. All these guys were fantastic. It was just a joy to work with them. I felt very, very special."
Prostate cancer is one of the most common types of cancer and the second-biggest cause of cancer death for men in the United States. While some types of prostate cancer grow slowly and may need minimal or even no treatment, others are aggressive and can spread quickly, according to the Mayo Clinic.
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