Reese Witherspoon plays tennis with a friend on May 23, 2012 in Los Angeles, California. Credit: Vince Flores/AFF-USA.COM

Reese Witherspoon is one fit mama-to-be!

The This Means War star, 36, hit the tennis courts in L.A. with a pal Wednesday afternoon, clad in a blue tank-top and knee-length black athletic pants.

Witherspoon--who is currently expecting her and husband Jim Toth's first child together--is doing her best to stay active throughout her pregnancy. The actress also spent some time on the court May 16, and has been going out on regular hikes with friends and family. (Witherspoon was photographed taking a lengthy hike with a pal the day Us Weekly broke the news of her pregnancy on March 21.)

More recently, the Oscar winner bonded with kids Ava, 12, and Deacon, 8, and her troubled dad John Witherspoon on a family hike through the Santa Monica Mountains May 19. The retired physician is currently embroiled in a legal battle with his estranged wife--and Reese's mother--Betty, who is requesting conservatorship over her husband, who she believes suffers from early-onset dementia. (John wed Patricia "Tricianne" Taylor in January--Betty filed a suit alleging he committed bigamy, and is incapable of looking after himself.)

"Reese is devastated," a source tells Us of the family's recent troubles. "She wants her mom protected and her dad to get help."