A rare, unpublished letter from Ronald Reagan’s formative Hollywood years, before he became president, was recently discovered and is what scholars are calling "classic Reagan" -- offering insight into his fight against the Communist “menace,” and describing the Russians as “brutal aggressors.”

In 1961, while an actor with the No. 1 show in its time slot, Reagan received a letter from a concerned woman in Van Nuys, Calif., criticizing him for playing a sympathetic role to Communism in the television show, "The Iron Silence," which aired on September 24 that year. At the end of the episode, Reagan’s character releases two Hungarian prisoners, saying: “In all my life, I never knew freedom until I saw you lose yours.”

For the leader who British Prime Minister Margaret Thatcher credited with ending the Cold War without firing a single shot, Eleanor Houston’s letter affected Reagan enough that he would respond in classic Reaganesque style, telling her she was mistaken about any Russian sympathies, and that he'd even be willing to portray Nikita Khrushchev, the Soviet leader at the time, "if it would help alert America to this menace."

The Gipper took the opportunity to jab the leader of the Soviet Union and point out that no one in Hollywood was telling the story from an anti-Communist point of view.

“Your letter, I must confess, has somewhat startled me,” Reagan replied. “It is true I played a Soviet officer, but the idea was to use my role to point up the inhumanity of the Soviet creed.”

Reagan pointed out that many people praised the play for its portrayal of the Russians as the “brutal aggressors” they are known to be.

“I’m sorry if you did not interpret the story in this light, but I assure you our aim is anti-Communist and for that matter anti-Russian,” Reagan wrote.

He concluded: “Frankly, I’d play Khrushchev in the screen if it would help alert America to this menace.”

Until now, the letter had been in storage with Houston's family for more than half a century, but the Raab Collection is now selling the rare letter for $20,000.

"It's quintessential Reagan," Douglas Brinkley, the author of "The Reagan Diaries" and a history professor at Rice University, told Fox News. "It's all rolled up in one: his humor, his righteous anti-Communist stance, and his storied Hollywood career."

During the 1950’s and 1960’s Reagan used television as a platform to deliver his anti-Communist message to the American people through his work for the General Electric Theater. The TV series ran for 10 seasons from 1953-1962.

Brinkley points out that most people would've thrown the letter away, but Reagan didn't want anyone to think he was even slightly sympathetic to Communism.

"It’s a great document to show how much Reagan treasures the idea of American freedom and how disdainful he was of Soviet totalitarianism," Brinkley said.

He added that Reagan biographers will use the letter primarily because of the line about Khrushchev.

“We see in this letter Reagan’s wit, humor and also his charity in his willingness to sit down and write a letter like this to a concerned fan,” Paul Kengor, author of "The Crusader: Ronald Reagan and the Fall of Communism" and professor of political science at Grove City College, told Fox News. “In many ways, this letter is classic Ronald Reagan.”

Kengor called it a real gem.

“I’ve watched that old GE Theater episode, ‘The Iron Silence,’ in which Reagan played the Russian communist,” Kengor said. “It must have indeed startled him that someone such as this letter-writer could be so sensitive as to interpret Reagan’s role as a negative. No doubt, just as Reagan said in his reply to Miss Houston, he played the role to underscore the inhumanity and injustice of communism. His concluding line saying that he’d be willing to play Khrushchev in order to further expose the brutality of communism is just great.”

Nathan Raab, Principal at the Raab Collection, called it a “remarkable letter” showing Reagan’s intention to use television as a platform to prop up American freedom.

“Ronald Reagan’s political career had a profound impact on the United States, and his firm stance against Communism (and its standard-bearer the Soviet Union) is what first brought him to the attention of conservatives and led directly to that political career,” Raab said. “These beliefs became core tenets of his being, and remained so until the seemingly monolithic power of Communism in Europe teetered and fell during and just after his presidency.”