Using materials from the Russian Foreign Ministry archive in Moscow (combined with previously obtained Brazilian and U.S. sources), this research note presents fresh evidence about Soviet-Brazilian relations and the October 1962 Cuban missile crisis, supplementing a detailed, two-part article published in the Journal of Cold War Studies in 2004 exploring Brazil's secret mediation between John F. Kennedy and Fidel Castro at the height of the crisis. The new evidence illuminates a previously hidden “double game” that Brazil's president, João Goulart, played during the crisis as he alternated between meetings with the U.S. ambassador and Nikita Khrushchev's recently arrived envoy (Brazil and the Soviet Union had just restored diplomatic relations after a fifteen-year break). The new evidence from Moscow suggests that Goulart, who vowed solidarity with Washington and even toasted Kennedy's “victory” when talking to the U.S. ambassador, took a completely different approach when speaking to Soviet officials, expressing strong sympathy and even support for Khrushchev.