Nick and Vanessa Lachey have confirmed the sex of their baby.

The couple are expecting their first child, with Vanessa due to give birth in September. The TV host has now revealed she is having a boy.

"It's a BOY," Vanessa announced on her website on Wednesday. "Nick and I are incredibly excited to share the news that we are expecting a baby boy. We can't wait to meet him soon (sic)!!!"

Nick first announced that Vanessa was pregnant while co-hosting US TV show Live! With Kelly earlier this year.

The 31-year-old beauty has coped well with the pregnancy and the pair recently celebrated the impending new arrival by going on a babymoon to St. Lucia.

Vanessa posted a stunning photograph of herself taken by Nick earlier this week. She was posing in a bikini by the water as the sun set.

"Let's embrace our changing bodies!" she wrote on her Twitter page as she encouraged other pregnant women to post pictures too.

Before they found out the sex of the baby, Nick and Vanessa revealed they were having trouble choosing baby names. While they had agreed on some names for a girl, they couldn't settle on something for a boy.

"We've been yelling them around the house to see how they sound and we call them to come to us," Vanessa laughed to Us Weekly.