Diehl was born in
West Berlin. His father is actor Hans Diehl, his mother is a
costume designer, and his brother is a composer. His family was frequently moving around. Diehl spent his childhood in
Auvergne, France, and moved back to
West Germany when he was nine years old. The family lived in
Hamburg,
Vienna, and
Düsseldorf. Growing up in a family of artists, at the age of 18, he played Franz Moor in a school theatre production of
Die Räuber by
Friedrich Schiller. After passing the
Abitur exams, Diehl studied acting at the renowned
Hochschule für Schauspielkunst Ernst Busch in Berlin. In 2000, he was named one of European film's
Shooting Stars by the
European Film Promotion. In 2009, Diehl played
Gestapo major Dieter Hellstrom in
Quentin Tarantino's
Inglourious Basterds. In 2024, he appeared in the fantasy-drama
The Master and Margarita, based on the novel by
Mikhail Bulgakov, playing a
devil-like character called
Woland. And in the historical drama
Bonhoeffer. His upcoming projects are
The Disappearance, in which he portrays
Josef Mengele, and the action film
Control. In 2025, Diehl appeared in
Lucile Hadžihalilović's fantasy-drama
The Ice Tower. ==Personal life==