What custom creation did Scarlett Johansson showcase at a major film festival that was envisioned just for her?

Scarlett Johansson wore a custom gown designed by Valentino's Alessandro Michele at the Toronto International Film Festival for the premiere of her directorial debut, 'Eleanor the Great.' The dress was described as being 'envisioned entirely for [Johansson]' according to a post on Valentino’s official Instagram Story.