Deep Throat (Watergate)

Deep Throat is the pseudonym given to the secret informant who provided information in 1972 to Bob Woodward, who shared it with Carl Bernstein. 
Woodward and Bernstein were reporters for "The Washington Post", and Deep Throat gave key details about the involvement of U.S. President Richard Nixon's administration in what came to be known as the Watergate scandal. 
In 2005, 31 years after Nixon's resignation and 11 years after Nixon's death, a family attorney stated that former Federal Bureau of Investigation (FBI) Associate Director Mark Felt was Deep Throat. By then, Felt was suffering from dementia and had denied being Deep Throat, but Woodward and Bernstein then confirmed the attorney's claim.
Hal Holbrook played Deep Throat in the 1976 political thriller "All the President's Men".