Kate Winslet Taking Over Nicole Kidman's Role

TUESDAY JANUARY 08, 2008 03:50 PM EST

Kate Winslet is stepping in to take over the role vacated by Nicole Kidman in The Reader, PEOPLE has exclusively learned.

Sources confirm that, in fact, Winslet was originally offered the role but couldn't commit due to schedule conflicts. Kidman pulled out of the film after announcing her pregnancy.

"Kate was offered it first before Nicole but couldn't do it but the dates clashed with commitments to Revolutionary Road," says an insider. "So the dates changed, Nicole then got pregnant and now it has come back to Kate."

Based on German author Bernhard Schlink's bestselling 1995 novel – and Oprah's Book Club selection – the film is about an affair between a teenage boy and an older woman in post-WWII Germany.

"Actually everyone is happy now – Nicole as she has a baby on the way, Kate because she has this great role she originally wanted to do, and the filmmakers are too," says the source