Reese Witherspoon and her son Deacon
10/22/2012 AT 02:30 PM EDT
is back in action.
The new mom, who just three weeks ago gave birth to Tennessee James
– her son with hubby Jim Toth
– was spotted out and about on Saturday to support her eldest son, Deacon.
Appearing all smiles at an L.A. soccer field near her Brentwood, Calif., home, the star, 36, looked casual in a baseball cap, jacket and rolled-up pants.
Witherspoon's little athlete, who turns 9 this week, sported an orange uniform while munching on a snack.
Becoming a mom for the third time doesn't seem to have slowed Witherspoon down. The actress, who also has a daughter, Ava, 13, with ex-husband Ryan Phillippe
, was spotted out
earlier this month running errands in Santa Monica, Calif.
The actress and Toth, 42, have been reveling in their family time together. "Everyone is bonding with the baby," a source told PEOPLE
after baby Tennessee's birth. "Jim has had a lighter workload and has been spending a lot of time at home with the baby as well."