The exclusive interview will air April 30 on ABC. It will also be featured on "World News with Diane Sawyer," "Good Morning America" and "Nightline."
Knox was studying in Italy before she spent four years in a prison there after the murder of her roommate. Knox was convicted of the crime in 2009. She appealed, won a new trial, and was acquitted and set free in 2011.
The interview is timed to the release of her book, "Waiting to be Heard."
ABC News and the Associated Press contributed to this report.