Mazel tov! Baby No. 3 is on the way for Reese Witherspoon, sources tell Us. It will be the actress' first baby with Jim Toth, who she married a year ago; her two children, Ava, 12, and Deacon, 8, belong to ex-hubby Ryan Phillippe. "The timing is right," a source says. "She's so happy!" But Reese, who turns 36 tomorrow, is "not planning to announce" the pregnancy, which is about 12 weeks along, another source adds. Click for more on the happy rumors. (More Reese Witherspoon stories.)