'The Voice' coach also says ex-wife Miranda Lambert never caught him cheating in declaration against 'InTouch Weekly.'
Blake Shelton isn't laughing off a tabloid report that claimed he has a drinking problem.
The 39-year-old country singer filed a $2 million lawsuit in October over an InTouch Weekly story that reported he checked into rehab after his divorce from Miranda Lambert, claiming defamation and false invasion of privacy.
Now, in a declaration obtained by ET, Shelton says he was "furious" to see himself depicted as "a man who cannot function, cannot do his job, and is on the brink of death without treatment."
WATCH: Gwen Stefani Says Blake Shelton 'Saved' Her After Gavin Rossdale Divorce
"Not only was I not in rehab or headed to rehab when it was published, but I also do not have a drinking problem," he claims in the declaration against InTouch's parent company, Bauer Media. "All of this was false and went so far beyond prior stories about me that I had previously denied with humor."
The Voice coach reveals that his professional reputation is "extremely important" to him and this tabloid story jeopardized that.
"I do not drink excessively, binge drink, or have a drinking problem. I do not, as the Rehab Story alleges, drink vodka before 11:00 a.m. I am never drunk, intoxicated, or unable to perform my job on The Voice or elsewhere," he writes.
"I do not slur my words or stumble when I drink," he adds. "I have never urinated on a mailbox in public, or otherwise. I did not start drinking at 14. I did not start drinking as a teenager. I did not start drinking to cope with my brother's death."
Shelton also takes offense to accusations that his marriage to Lambert, who he split from in July, ended because he was unfaithful, declaring that he did not drunkenly do anything to destroy their relationship.
"My ex-wife Miranda Lambert did not catch me with a bunch of naked women in our Tennessee home one night," the singer, who has since begun a high-profile romance with Gwen Stefani, says.
"Ms. Lambert did not tape me while drinking and then show me a video of myself the following day. During our marriage, Ms. Lambert never begged, demanded, or asked me to go to rehab...I did not handle my first divorce by drinking, nor has my drinking increased or escalated since my divorce from Ms. Lambert," he continues.
In February, Bauer filed a motion to strike Shelton's lawsuit and claimed they had not defamed him and that they stand by statements made in the story that he has a drinking problem, using Shelton's tweets as evidence.
"Shelton ignores that he has staked his reputation on heavy drinking: he tweets more than 15 million Twitter followers almost daily with messages crowing about how much he drinks and is famous for his signature Twitter tagline, 'Drunk,'" Bauer's attorneys write in a filing obtained by ET.
Shelton responds in his declaration, admitting that he will often joke about alcohol -- "part of my schtick with my fans" -- but arguing that "in no way indicates that I have an actual problem with alcohol."
InTouch had no comment when ET reached out.
Meanwhile, the GRAMMY winner recently released his new single, "Came Here to Forget." Check out all the clues that it's about Lambert and Stefani in the below video.