The cue card guy on the “Late Show with David Letterman” has lost his job after reportedly assaulting an Emmy-nominated writer on the late night show.

“I know I shouldn't have put my hands on him,” the 69-year-old Tony Mendez told the New York Post. “But this has been coming for a long time.”

The altercation between Mendez, who has regularly been shown on-air during the broadcasts, and Bill Scheft occurred on Oct. 9 before the show's Thursday taping. But it was set off by a verbal confrontation with Scheft, a 15-time Emmy nominee, a day earlier, Mendez told the Post.

“Bill was always undermining me — making himself out as Dave's No. 1,” Mendez said, “trying to pretend that I wasn't even in the room . . . little passive-aggressive things.

The three were rehearsing at the Ed Sullivan Theater when Mendez said he reacted to one of Scheft's interruptions, telling him, “I know what I'm doing. Get off my back.”

Letterman interrupted and said, “Tony, your sour disposition isn't helping,” Mendez recalled, adding that he snapped back, “You're the one who has the sour disposition ...' ”

Mendez said he was upset by the blowup with his boss of 21 years.

“I wanted to tell Dave how much that hurt my feelings,” Mendez said. “And then I realized that this is what Bill was doing. He was trying to create a wedge between us so Dave would think I was an a-hole.”

Mendez said that the next morning when he got to work, he snapped and went after Scheft. Two CBS sources told the Post that he threw Scheft against a wall.

“I just grabbed him by the shirt,” Mendez said. “He was very surprised. He didn't say a word. He was cowering, his eyes were real big, he probably peed a little bit on his pants.”

Security interceded and Mendez was escorted from the theaters. The following Monday he was told by the show's executive producer that he was terminated, though the show offered to pay his salary and maintain his health care coverage until Letterman's retirement in May.

“Dave had nothing to do with this at all,” Mendez said. “He was oblivious to my problem with Bill Scheft. But now that CBS is involved, they probably said to Dave and other people, ‘Because of what he did, he can't be there. Because we're CBS and have zero tolerance for that kind of stuff.’ ”

Mendez remains a Letterman fan.

“Dave has never let me down,” he said. “He is the best, the most generous boss I have ever had. Dave would never do anything to harm me.”

CBS did not immediately respond to TheWrap's request for comment late Sunday.