Fresh on the heels of her sexy December cover for FHM Australia where she showed off her post-baby bod, Isla Fisher is gearing up to premiere her new movie, 'Confessions of a Shopaholic.'

ET is with Isla on the set of her new comedy, where the redhead is hard at work shopping while shooting scenes at Barneys New York with co-star Leslie Bibb.

Funny Isla, who gave birth to daughter Olive in October 2007, is stepping into the stilettos of Becky Bloomwood for her new role. Becky is a journalist at a stuffy financial magazine whose dreams of a designer wardrobe stretch her credit card limits to the max. Leslie plays her romantic rival, Alicia. The beloved series of books, written by Sophie Kinsella, begins in London and segues to New York where Becky becomes a personal shopper at Barneys.

Hugh Dancy plays Becky's public relations beau, Luke Brandon, and Joan Cusack, Kristin Scott Thomas, John Lithgow and John Goodman also star in the comedy. The film, directed by P.J. Hogan ('My Best Friend's Wedding'), arrives in theaters on February 13.