Bush Hager, 31, announced on Wednesday's edition of "Today" she expects to deliver the baby this spring.
"I'm fired up. I'm looking forward to it," the two-term president said in a phone call to "Today," the morning program for which Bush Hager is a correspondent. "I could barely contain the news."
"We're both really thrilled," former first lady Laura Bush told People.com. "We've been looking forward to being grandparents for a long time and we're very excited about it."
"We're so excited," Bush Hager told People.com. "We can't wait."
Bush Hager married Henry Hager in 2008. She said they will wait until the baby is born to see if it is a boy or girl.