Career: In 1956, Vaughn was signed by Burt Lancaster's production company, but was drafted into the army shortly afterwards. On his return to Hollywood, he spent the next few years playing small roles in movies and TV series such as The Ten Commandments and Gunsmoke. In 1960 he received an Oscar nomination for The Young Philadelphians and was one of The Magnificent Seven. TV show The Lieutenant followed, and he became a major global star thanks to The Man from UNCLE in 1964. Vaughn has also starred in Bullitt, The Towering Inferno, Battle Beyond the Stars, and SOB, and continues to regularly crop up on the big and small screens. He starred in as con-artist Albert Stroller in the BBC drama Hustle between 2004 and 2012, before shifting his attention to Coronation Street to appear as rich American Milton, the love interest of Sylvia Goodwin.

Career: McCallum became an assistant stage manager, but National Service interrupted his career. He made his film debut in 1957's These Dangerous Years, and appeared in numerous British movies before moving to Hollywood in the early 1960s. He landed roles in Billy Budd and The Great Escape but it was his performance as Illya Kuryakin in The Man from UNCLE that made him a household name in 1964. The series ran until 1968, and a spin-off TV movie was made in 1983. He also released four albums in the 1960s. Other major projects include Colditz, The Invisible Man, Sapphire and Steel, Mother Love, Hear My Song, and Cluedo. Since 2003, he has starred in popular American drama NCIS, playing forensics expert Dr Donald 'Ducky' Mallard.