Frederick Simonsson

 was the art collector for the king of Sweden. He liked his job. He discussed art with the Eighth Doctor. He wanted to buy many of Tardelli's artworks. He showed the Doctor photos of his collection. Lucie Miller later showed him the Doctor's TARDIS. When the Headhunter and Karen stole the black diamond, he joined the Doctor in trying to retrieve it. Upon meeting Tardelli, who was hiding inside the diamond, he was disappointed in man whose art he admired. (AUDIO: Grand Theft Cosmos)