Reese Witherspoon and son Deacon on October 20, 2012 in Brentwood, California. Credit:

Who says soccer moms can't be sexy?

Three weeks after giving birth to son Tennessee James, Oscar-winning actress Reese Witherspoon was spotted happily doting on her older son, Deacon, at a youth soccer game in the Brentwood neighborhood of Los Angeles. (Deacon, 8, is Witherspoon's son with ex Ryan Phillippe; the former couple also have a daughter, Ava, 13.)

Dressed casually in sneakers, a hooded jacket, rolled-up jeans, and a blue baseball cap, the blonde Devil's Knot star couldn't hide her megawatt Hollywood smile as she and her CAA agent husband Jim Toth cheered Deacon and his team from the sidelines. At halftime, the beaming mother-of-three joined her little athlete on the field for a quick chat.

Witherspoon and Toth, who wed in March 2011, have been adjusting comfortably to their new life since welcoming Tennessee James into the world on September 27.

"The entire family is thrilled," Witherspoon's rep told Us Weekly in a statement.

That includes the tyke's new brother and sister, who are eager to bond with the new bundle of joy.

"The kids met the baby the first day at the hospital," a source told Us earlier this month. "Deacon is excited to have a brother. And Ava can't wait to babysit!"