The sexy star announced the news to fans on her Twitter.com blog on Wednesday (16Mar11), writing, "Thom and I are glad to declare we are having a baby a baby girl. We are pleased."
Brook, who earlier dated Titanic star Billy Zane and action man Jason Statham, was first lovingly linked to Evans in late 2010.
Paradoxically, Evans was a partner of Brook's ex, Danny Cipriani, while playing for the London Wasps between 2004 and 2006.
