Agnès B. boutiques have long sold T-shirts bearing the words, “J’aime le cinéma,” as well as skirts and dresses cut from fabrics inspired by film stills. But Agnès Troublé, the Paris-based fashion designer behind the brand, doesn’t just love the movies. She underwrites them, too.

In 1997, Ms. Troublé founded the filmmaking company Love Streams Agnès B. Productions — named for John Cassavetes’s 1984 movie, “Love Streams.” This season, it is co-producing “Mister Lonely,” an official selection of the Tribeca Film Festival, which begins tomorrow. Directed by 35-year-old filmmaker Harmony Korine (“Kids,” “Gummo”), “Mister Lonely” centers on a Michael Jackson impersonator (Diego Luna), who goes to live with other celebrity look-alikes on a commune in the Scottish Highlands. Ms. Troublé, 67, who creates clothes for women and men, will attend the film’s April 29 Tribeca premiere, and will host its after-party.

The designer has helped produce about 30 films. For “Mister Lonely,” she designed the tea-length, white, crepe halter dress worn by the film’s Marilyn Monroe character (Samantha Morton), as well as all of Mr. Luna’s Michael Jackson costumes. The “Mister Lonely” soundtrack ($15) and a limited-edition book ($24), which includes the script and stills from the movie, are now available for purchase at Agnès B. stores in America.

For “Mister Lonely” screening times and ticket information, visit tribecafilmfestival.org. Agnès B. Manhattan stores are situated at 103 Greene St., between Prince and Spring streets, 212-925-4649; 13 E. 16th St. at Fifth Avenue, 212-741-2585, and 1063 Madison Ave., between 80th and 81st streets, 212-570-9333.