Ravil Isyanov has died at the age of 59.
The actor passed away in Los Angeles on September 29 following a long cancer battle.
"Even while battling this awful disease, Ravil remained brave and resilient, bringing his best to the set and working up to the very end," Isyanov's manager, Frederick Levy, told Entertainment Weekly. "He will be dearly missed."
Levy told PEOPLE that "Ravil was one of a kind. He was a true gentleman, extremely generous and incredibly talented."
Isyanov is said to have received his cancer diagnosis while working on NCIS: Los Angeles. The type of cancer the actor had was not disclosed.
"He knew that his future looked bleak because of the cancer and he let producers know, and if they wanted to write him off, they might want to do it, soon… I just thought it was really sweet that they were able to give him a proper send off," the manager told the publication.
Tanya Kleckner of HRI Talent, told EW that Isyanov "was one of kind and a true talent."
Isyanov played Russian mobster Kirkin on NCIS: Los Angeles and made appearances in seasons 4, 7, 9 and 10.
He also made appearances in Marvel's Agents of S.H.I.E.L.D., Bones, Fringe, Buffy The Vampire Slayer and 24. He recently starred in GLOW on Netflix. He will also appear posthumously in Blonde and 25 Cents Per Minute, which are both in post-production, Deadline reported.
Isyanov was born in Russia before moving to Los Angeles in 1998.
He is survived by his wife, Erika, daughter Gulya, as well as his grandchildren, sister and his ex-wife Marsha.
Fans posted tributes to the late star on social media.
"One of the most entertaining Russian actors I've ever seen..." one fan tweeted.
"Rest in Peace Kirkin," another user lamented.
"Ravil Isyanov was absolutely amazing as Kirkin on @NCISLA. His passing is so tragic. May he Rest In Peace," a third fan wrote.