Veronica dated Duncan Kane until approximately September 2005. Both Veronica's mother Lianne Mars and Duncan's mother Celeste Kane were against their relationship, though Veronica did not find out why until much later. Some time prior to Lilly's death, Celeste revealed to Duncan that his father, Jake, had had an affair with Lianne, and that Veronica might be his half-sister. Duncan broke up with Veronica because of this, but did not explain his reasons for doing so. Keith Mars later had a paternity test which proved that he is her father, not Jake Kane.