Career: Harmon's first TV appearance came as a child in an advert alongside his father. His break into came via a 1975 episode of Police Woman. His CV includes everything from glossy soaps such as Flamingo Road, to big-screen offerings, including Beyond the Poseidon Adventure and The Presidio. He gained much acclaim for his role in medical drama St Elsewhere, playing a doctor who contracted HIV; he was named People magazine's Sexiest Man Alive while appearing on the show. He also featured in the films Freaky Friday, Chasing Liberty and TV series The West Wing and JAG. These days he's best known for his role as agent Leroy Jethro Gibbs in NCIS, a part he's played since 2003.

Career: Bello got her big break when producers Kerry Lenhart and John J Sakmar cast her in the spy show Mr & Mrs Smith in 1996, remembering her from a failed pilot remake of the classic TV series 77 Sunset Strip. The show was cancelled after eight weeks on the air. Then came a spot on ER in 1997 as Dr Anna Del Amico for the final three episodes of the third season. The show's producers were so impressed with her that they asked her back as a regular on the series. She quit after just one run to focus on movies. Roles in Mel Gibson vehicle Payback and quintessential chick-flick Coyote Ugly followed, and later projects have included such critically lauded work as A History of Violence and The Cooler. Her status as an A-lister was confirmed when she was chosen to replace Rachel Weisz in the third instalment of The Mummy franchise. Since then, she has appeared in The Private Lives of Pippa Lee, The Company Men, Grown Ups and Abduction.

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.