The diplomatic history of World War II includes the major foreign policies and interactions inside the opposing coalitions, the Allies of World War II and the Axis powers, between 1939 and 1945. High-level diplomacy began as soon as the war started in 1939. British Prime Minister Winston Churchill forged close ties with France and sought close ties with the United States, especially through his relationship with President Franklin Roosevelt. When Russia joined the war in June 1941, the Grand Alliance expanded to a three-way relationship among Churchill, Roosevelt and Joseph Stalin of the Soviet Union. American diplomacy stepped up after it entered the war in December 1941 and was bolstered by large quantities of financial and economic assistance, especially after the Lend-Lease programme b