Gillian Anderson Popped It Out! BY Robyn Good on October 22, 2008 | Comments: one commentRelated : Gillian Anderson Gillian Anderson has given birth to a baby boy. Gillian and boyfriend Mark Griffiths already have a one year old son Oscar. Gllian gave birth to Felix Griffiths on October 15th in London. Felix weighed 6 lbs 150z.