Impressed by her performance in "Under the Skin", Woody Allen cast her in "Sweet and Lowdown", a romantic comedy about a fictional jazz guitarist in the 1930s (played by Sean Penn) who regards himself as the second greatest guitarist in the world. Morton played Hattie, a mute laundress and the love interest of Penn's character. The film was released in September 1999, to wide critical acclaim and moderate success at the box office in the arthouse circuit. George Perry for BBC.com found her to be "extraordinary" as an "adoring mute who suffers [...] She uses her eyes to convey meaning, reviving techniques of silent cinema". Morton earned Academy Award and Golden Globe nominations for Best Supporting Actress for her role, which was especially notable, considering the fact that she does not utter a single word of dialogue in the film. During a 2007 interview with UK's "The Guardian", she remarked that her Oscar nomination meant "incredible things for me in the States. I'm grateful for that. It means that [...] I'm able to support the industry".