Glamour Reese Witherspoon sends a huge and heartfelt congratulations to Reese, Jim, Ava & Deacon on this happy news!!

Reese Witherspoon is a mom for the third time.

The actress gave birth to a son, Tennessee James Toth, on Thursday, Sept. 27, her rep tells PEOPLE exclusively.

“Reese Witherspoon and husband Jim Toth welcomed Tennessee James into their family today,” the rep says. “Both mom and baby are healthy and the entire family is thrilled.”

The baby is Witherspoon’s first child with her husband, whom she married in March 2011. She is already mom to Ava, 13, and Deacon, 8½, from her prior marriage.

In March, a source told PEOPLE that the actress, 36, was eager to have another child. “Right after the wedding, Reese expressed a desire to have a baby with Jim,” said the source. “Reese has been very open with her kids about her plans to expand the family.”

Witherspoon, who initially kept her pregnancy under wraps, subsequently showed off her baby bump all around the world over the spring and summer — from appearances at the Cannes Film Festival to lunches and errands at home in Los Angeles. “Frankly, I’m feeling very round,” she told reporters in June.

– People.com