According to the Evening Standard, the star used the services of a surrogate to have a second child.
The Basic Instinct star already has a 5 year-old son, Roan, who was adopted in May, 2000.
A source told the newspaper, "Sharon has paid to have a surrogate carry her baby and it was born yesterday in the US. She’s going to be flying back to pick up the child as soon as she can."