The 26-year-old Dutch man, currently serving a 28-year sentence for the 2010 murder of Stephany Flores, will marry 24-year-old Leidy Figueroa on May 22, according to CBS News.
Figueroa met van der Sloot when she visited another inmate at the Peruvian prison in 2010. They started a relationship at the prison, which allows conjugal visits, and she's now five months pregnant with his child.
When he finishes his 28-year sentence, Van der Sloot will be extradited to the United States, where he is the prime suspect in the 2005 disappearance of American Natalee Holloway in Aruba. Her body was never found.
Figueroa told CBS News' Crimesider that van der Sloot is a "new person."