Mason Walter Wilkerson was born Wednesday afternoon and weighs 9 pounds, People magazine reported. It is the first child for Hart, 29, and husband, Mark Wilkerson, 28, lead singer and guitarist for rock band Course of Nature.
"He was a little stubborn, but all is well," Hart told People. "Everyone is well and we are all relieved."
Hart and Wilkerson met in May 2002 when she introduced his band at a Kentucky Derby event in Louisville, Ky., according to the magazine.
The new parents tied the knot in Florence, Italy, in July 2003, three months after "Sabrina, the Teenage Witch," a popular sitcom about a high school student with magic powers, ended its seven-year run.