The "Water for Elephants" star, who already has daughter Ava, 13, and son Deacon, nine, from her first marriage to Ryan Phillippe, is thought to be expecting a son with her second husband Toth, reported Contactmusic.
"They're both really happy to be having a son, but especially Jim as it's his first. He's over the moon about it," a source said.
Witherspoon was rushed to hospital with pregnancy complications in August but it was just a scare and mother and baby are doing fine.
"Jim's still nervous after Reese's scare and hospital stay. But he just can't wait to hold his son in his arms," the source added.
