The couple have been an item for eight months now and as a result the girlfriend is allowed to visit Van Themsche in gaol.
The woman tells Het Laatste Nieuws: "I am a normal girl. I come from a normal family. I never hit on bad boys. I love dancing, fitness and painting the town red with my girlfriends. I studied remedial education in Ghent. I'm just like everybody else."
Van Themsche is believed to be a friend from the woman's youth. They got into contact again a while ago and became an item. As a result the woman now has unhindered access to the killer.
The 25-year-old woman told the daily her parents were not au fait with the relationship and have not been told she is expecting.
The woman says she readily accepts her pregnancy may cause distress for relatives of Van Themsche's victims but adds: "I'm in love with him. It's not something I consciously chose."
In 2007 Hans Van Themsche, who comes from a far-right background, was convicted of killing a 2-year-old toddler and her Malian au-pair with a rifle. He also wounded a Turkish woman in his spree of violence targeting members of the immigrant community.