By Jill Serjeant

LOS ANGELES (Reuters) - "Mad Men" actor Jared Harris said on Monday the graphic suicide of his English gentleman TV character Lane Pryce in the season's penultimate episode, was intended as a "fuck you" gesture to his fellow advertising executives.

And in a season of shocks on the Emmy-winning TV drama, Harris said he had kept the macabre plot twist secret for months, even from his own agent and manager.

Harris was written out of the show when his character's dirty financial tricks are discovered by Jon Hamm's Don Draper and a shamed and angry Pryce hangs himself in his office.

But the episode was filmed in the summer of 2011 and kept under wraps from the public by the cast and crew.

"I couldn't tell my agent, I couldn't tell my manager, I couldn't take part in TV pilot season this year because I knew that if I had signed on to a new show, people would know something had happened and it was in my interest to keep it as big a surprise as possible," the English actor told reporters on Monday.

Harris, the son of the late Irish actor Richard Harris, said he spent two hours in make-up for his jarring final scene, where Pryce's limp dead body is found by members of the ad agency hanging on the back of his office door.

"He was angry and it was an expression of his anger...His choice of doing it there was a fuck you to the office and the people who work there, particularly to Don," Harris said.

"He is trying to make them feel bad about what he has done...It was a cowardly thing to do. He did it to try and hurt them, the way that he feels they have hurt him."

Pryce's initial attempt to kill himself in his new Jaguar fails, in what Harris on Monday called a hilarious dig at the car's unreliable reputation in the 1960s and the ad agency's prestigious new contract.

Harris, 50, said he "just fell off the chair laughing" when he first read that part of the script.

The actor was given two episodes' notice of his exit by creator Matt Weiner and although he was dismayed to leave the TV series, he said he "could see from an acting point of view it was to my benefit to go out with a bang rather than a whimper."

With his character's demise now broadcast, Harris is free to look for another job on television, and he will next be seen playing U.S. Civil War General Ulysses S. Grant in Steven Spielberg's upcoming movie "Lincoln."

"Matt was very kind to me. He allowed me to go and shoot the Spielberg movie while I was shooting these episodes. They arranged the 'Mad Men' schedule for me so I could go and shoot 'Lincoln'," Harris said.

The season finale of "Mad Men" will be broadcast on AMC on June 10.

(Reporting By Jill Serjeant, editing by Piya Sinha-Roy)

• A Permanent Economic Emergency