 Holmberg is a frequent guest on Swedish television and radio for discussions about science fiction and other literature; in 2010, this has often included discussions of his relationship with fellow SF fan Stieg Larsson and the question of whether Larsson left behind fourth or even fifth novels in his series.In 2011, he published a book in collaboration with Dan Bursteing and Arne De Keijzer, titled "The Tattooed Girl