The sources said the agreement struck over the weekend will reunite Abdul with "American Idol" creator Cowell and round out the panel of distinguished judges that also includes Antonio Reid and Cheryl Cole.
Abdul left "Idol" to take part in the short-lived CBS series "Live to Dance" under a contract that barred her from joining another show, The Reporter said. The 11th-hour negotiations produced an agreement that seemed to satisfy both camps.
"X Factor" began taping in Los Angeles Sunday and will debut on Fox Sunday. The show is a talent competition based on a British series by the same name.
2014: The Year in Fashion [PHOTOS]