Charlie Chaplin, the iconic British actor with the toothbrush mustache, may have died in 1977, but it's actually his birth which is still a mystery.

MI5, a British Intelligence Agency has been trying to solve the mystery of Charlie Chaplin's birth since the 1950's. The secret file was finally released Friday by Britain's National Archives. No birth records seem to exist of Chaplin, who was born in London on April 16, 1889. In fact, the earliest official record that the MI5 can find on Charlie Chaplin is a passport that was issued in 1920.

What led British Intelligence to conduct such an extensive and ultimately unsuccessful investigation into the comedian? FBI Director, J. Edgar Hoover demanded that the MI5 open a file on Charlie Chaplin in 1952 because he believed the actor had communist links. The goal of the FBI was to have Chaplin banned from the United States.

Chaplin has given funds to communist front organizations, stated an MI5 liaison officer in Washington in October 1952. He has been involved in paternity and abortion cases.

Tracking by the FBI on Chaplin started way before the 1950's. The star of The Gold Rush, City Lights, and The Kid, moved to the United States in 1910, but by 1920 was considered to have left-wing friends and be involved in alarming activities.

Theories have circulated surrounding the comedian, some suggesting he was born in France instead of London, and others believing he was a Russian Jew named Israel Thornstein. The Guardian reports that the files associate him with suspected communists, including film critic and producer Ivor Montagu, and jazz musician Humphrey Lyttelton.

Files from the FBI on Chaplin contain over 2,000 pages, but the MI5 believed that Chaplin wasn't a threat, just a sympathizer.

The FBI and Hoover got their way in 1953 when they placed a ban on Chaplin from coming back to the U.S. after a brief stay in London. I am a victim of lies and vicious propaganda, said Chaplin about the U.S. ban. The comedian didn't try to fight it though, and instead moved to Switzerland where he died in his sleep in 1977.