Nicolas Cage is set to become a grandfather as his son Weston's wife is expecting a baby.

Weston told Closer Weekly magazine that the National Treasure star is delighted with the news, "He was ecstatic. His reaction was one of pure joy and bliss. Family is very important to us.

"My father and I actually speak everyday and Danielle [Weston's wife] and I texted him the ultrasound photograph which was actually confirmation of what we thought."

Mum-to-be Danielle added, "It is a boy. Big boy, weighs a lot. I'm so excited! This wasn't necessarily planned, but it is completely welcomed. We're so happy to be giving birth eventually."