The actress' rep said the couple have named their daughter Nancy Leigh, after Katherine's mum Nancy and her sis Margaret Leigh, reports the Daily Express.
The girl has also been given a nickname Naleigh.
The couple are posting pics of their new child on www.jasonheiglfoundation.org.
Photograph: Lucy Nicholson/Reuters
Shilpa Shetty to star in EastEnders?
AR Rahman plans free concert in Australia
Men find Katherine Heigl most desirable!
Love is not enough to make a marriage work
Meet Emma Watson, the student