The German model-turned-actress lent some much-needed glamour to the occasion in a stunning nude-coloured Herve Leger by Max Azria dress, which showed off her incredibly svelte figure and long legs.
The film's director Quentin Tarantino was full of praise for his leading lady, and said working with Diane was "wonderful".
Speaking on the red carpet at the premiere of Inglourious Basterds, he praised both stars Diane and Melanie Laurent.
"In the case of Diane it was really wonderful," said Quentin. "She had an idea of who she was basing the character on, and I had another idea of another actress, so I showed he that kind of work."