5:45 PM PT -- Tambor's responded, saying he's disappointed in the handling of these "false accusations" against him by Amazon and more so Soloway, and claims in his 4 years of working with her on "Transparent," the accusations were never revealed to him or discussed directly. He says he will continue to vehemently defend himself.

He adds ... "I can only surmise that the investigation against me was deeply flawed and biased toward the toxic politicized atmosphere that afflicted our set." He also says the "biggest heartbreak" is that the show is now in jeopardy.

Jeffrey Tambor is officially off his award-winning show, "Transparent" -- Amazon Studios announced the firing after investigating the sexual harassment allegations against him.

Amazon didn't release the results of its internal investigation, but easy to read between the lines ... since they canned their star. Tambor had previously claimed he was quitting the show after his former assistant and a co-star accused him. He later backed off that, but it's a moot point now.

"Transparent" showrunner Jill Soloway said, "We are taking definitive action to ensure our workplace respects the safety and dignity of every individual, and are staking steps to heal as family."