(CNN) - Amanda Knox's former boyfriend has written a tell-all book about their romance and the four years they spent in an Italian prison for murder.

In his newly released book "Honor Bound," Raffaele Sollecito says the two had nothing to do with the killing of Meredith Kercher in Knox's apartment in 2007.

Sollecito talked with Anderson Cooper about his relationship with Knox now.

Cooper: "You're still in touch with Amanda Knox?"

Sollecito: "Yes, we skyped yesterday."

Cooper: "You skyped yesterday. And what is that connection? What is that conversation like? I mean, you've been through something that nobody really else can imagine."

Sollecito: "Well, our conversation we talk about family, relationships with friends, about movies, books, music, CDs, anything I mean. Friends, we're like good friends. We are not almost, almost like a brother and sister. We passed through a lot together."

Cooper: "She's seeing somebody else, you're not involved romantically?"

Sollecito: "No, no. She has a boyfriend now and I'm moving on with my life separately."

Knox and Sollecito were released from prison last year after an appeals court overturned their conviction.

Knox is also writing a book that is due out in the spring.

CNN