Pregnant Reese Witherspoon Spends $600 on Maternity Jeans

Reese Witherspoon showing off her baby bump in Santa Monica, California on March 29, 2012. Credit: FameFlynet Picture

Reese Witherspoon is officially getting ready to dress her expanding waistline!

On Saturday, the actress was spotted shopping for maternity wear for the first time since Us Weekly broke news of her third pregnancy nearly two weeks ago -- and no mumus (yet) for this Oscar winner!

The This Means War actress, 36, dropped by the Paige Denim store near her home in L.A.'s Brentwood neighborhood with her daughter Ava, 12.

"They were both really sweet and polite," an observer tells Us. And Witherspoon did not leave the store empty handed -- spending nearly $600 on three pairs of jeans.

Witherspoon selected the Union Ultra Skinny in Caress ($199), Union Skyline Skinny in Capri ($199) and Union Skyline Ankle Peg in Optic White ($189) -- all with inset elastic panels at the waist for extra comfort and support.

Married for one year, Witherspoon and CAA agent Jim Toth 41, haven't yet made an official announcement about their happy baby news.

"[She wants to] let people figure it out," a source told Us. "She's been showing for a while." The baby-to-be will join Ava and Deacon, 8, Witherspoon's kids with ex-husband Ryan Phillippe.

"Settling down with Jim and raising a family is what she wanted," a second insider explained.