Bello's breakthrough came when the producers Kerry Lenhart and John J. Sakmar cast her as Mrs. Smith in the spy show Mr. & Mrs. Smith. The show was cancelled after just eight weeks on the air. Then came a guest stint on ER as the feisty pediatrician Dr. Anna Del Amico, in which she guest-starred in the final four episodes of the third season. Bello remained on the show for one season, departing after the medical drama's 4th season. The actress went on into movies landing a role in Coyote Ugly. She has been nominated for the Golden Globe award twice: for Best Supporting Actress in The Cooler (2003) and for Best Actress in A History of Violence (2005). In 2008 Bello starred in The Mummy: Tomb of the Dragon Emperor as Eve O'Connell.