Amanda Knox interview in April with Diane Sawyer

Amanda Knox, the college junior who spent four years in an Italian prison after being accused of murdering her British roommate, is telling her story to ABC News.

The network says Knox will sit down with Diane Sawyer for a prime-time interview airing April 30. The exclusive interview also will be featured on other ABC News programming.

Knox was an American student studying in Italy when, in 2007, she became the center of a murder case that seized the world's attention. She was convicted in 2009. But after an appeal, she was acquitted and released in October 2011.

The interview is timed to the publication of Knox's book, "Waiting to Be Heard,"  which is being published by Harper Collins on April 30. Knox reportedly was paid $4 million by Harper Collins.

Amanda Knox's former boyfriend Raffaele Sollecito maintained the couple's innocence in his own book, Honor Bound, which came out last fall. But Sollecito acknowledges that their sometimes bizarre behavior after her roommate's killing gave police reason for suspicion.

"Sollecito, then finishing his undergraduate studies in computer science, writes that he met Knox at a classical music concert at the Universita per Stranieri, the University for Foreigners, on Oct. 25, 2007 – a week before Kercher's death. He asked for her number, and she told him to come by the bar where she'd be working later that night. At the end of the shift, he writes, they took a walk, held hands and kissed. She accepted an invitation to come back to his apartment and spent the night.

Soon the couple became inseparable. She began spending the nights at his apartment. They shopped for groceries together, and took a sightseeing day trip to Assisi. Sollecito wrote about his first night in prison, saying he wavered between 'great waves of indignation and a nagging sense of guilt.' He said that while he knew he was innocent, he was angry at himself for having a foggy memory of the night of the killing because he and Knox had smoked marijuana," reported The Christian Science Monitor.