Tam trained at Guildford school of Acting. He is the son of actors Belinda Carroll and Simon Williams, Grandson of film actor Hugh Williams, and sixth generation actor on his mother's side. He has worked in Film, television and extensively in theatre including, N.T, RSC, Propeller, The Old Vic, Open Air Theatre Regents Park, Peter Hall company and has appeared in numerous West End productions including "Birdy" "Macbeth" "The Rivals" "Chariots of Fire" "Sunny Afternoon" ( Original cast, it won 4 Oliviers including best new musical). Television includes Lynda LaPlante's "Killer Net". Film includes "The Trench" and "Spectre". Tam lives and works in London with his wife, Dr Serena Williams, a consultant anaesthetist at St Thomas' Hospital. They have four children.