Reese Witherspoon

Reese Witherspoon is pregnant.

The actress, who turns 36 on Thursday, is expecting her first child with Jim Toth, her husband of nearly one year.

Witherspoon has two children -- Ava, 12 and Deacon, 8 -- from her previous marriage to Ryan Phillippe.

They are both thrilled . . . Jim and Reese are looking forward to having a bigger family at this point in life. They can take the time to enjoy the next stage and make sure the transition for all is easy and joyful, a source told People this week.

Rumors of Witherspoon's pregnancy actually began making headlines on Tuesday afternoon, when Us Weekly released the cover for their new issue, with the actress' photo blown up and the headline, Reese Is Pregnant!

Reese is right around 12 weeks . . . [they] have been trying to get pregnant, another source told Us.

The pregnancy announcement comes just off the heels of Witherspoon's world tour promoting her latest film, This Means War. Witherspoon, co-stars Chris Pine and Tom Hardy, along with director McG, have been busy promoting the romantic action comedy in places like South Korea and Brazil.

Witherspoon and Toth, a 40-year-old entertainment agent, were married on Mar. 26, 2011 at the actress' ranch in Ojai, Calif. The star-studded guest list included Renee Zellweger, Sean Penn, Scarlett Johansson and Robert Downey Jr.

He's wonderful . . . he's just a really great guy, and I feel really lucky, Witherspoon told Vogue shortly after last year's nuptials.

Witherspoon and Toth began dating in February 2010, following a two-year romance with Jake Gyllenhaal. Toth is an agent for Creative Artists Agency (CAA), which represents some of Hollywood's biggest names, including George Clooney, Meryl Streep and Brad Pitt.

Also Read: Reese Witherspoon Sizzles at 'This Means War' Premiere; Tom Hardy, Chris Pine Sport Suits [PHOTOS]