The elated singer is six months along with her first child – and it's a boy!

By Charlotte Triggs
Updated October 28, 2008 02:00 PM
Credit: Tony R. Phipps/WireImage

Country singer Jo Dee Messina is pregnant – and it’s a boy, she tells PEOPLE exclusively.

“I am in my third trimester now,” says Messina, 38, who celebrated her one-year anniversary with husband Chris Deffenbaugh, 28, last week. “We knew we wanted to have kids, but we just said, ‘Whenever it happens, it happens.’ And it happened!” she says. “We were both surprised at first. It’s such a lifestyle change. But then we’re like, ‘Wow, we’re going to be parents!'”

The star had been in the midst of a weight loss regimen when she found out the news. Realizing her weight wasn’t going down on schedule, “I took a test, and of course, I found out I was pregnant,” she says, adding that she’s “right on target” with her weight gain now, after about six months of pregnancy. “I’ve gained about 11 lbs., which is good,” she says. “I’m staying really fit. I run 30 minutes a day and weight train for an hour, five days a week. This is all baby!”

She s in such good shape, Messina even plans to run a five-mile race on Thanksgiving Day. “I’ll be eight months pregnant and running,” laughs Messina, who hopes to be back in shape and ready to shoot the video for her song “Unmistakable” just six weeks after giving birth. “It should be interesting!”

As will touring with a newborn baby on board when Messina hits the road next year. “I will take him on tour with me, but I’m like, ‘How do you do that?'” Messina says. “How do you do the bus? Who rides where? Band? Crew? Family? What safety devices do you need? I might grab one of the other singer moms like Sara Evans or Martina McBride and say, ‘Help me!'”