The Jonas Brothers singer wed the former hairdresser in 2009 and now they are expecting their first child.
The dad-to-be tells Eonline.com, "I was overjoyed. It's been the most exciting thing in my life so far... I'm excited and I'm nervous."
The couple has been documenting its hopes to start a family together on reality Tv show Married to Jonas, but Deleasa previously admitted they wanted to wait until a break in Jonas' schedule.
She said, "I cannot wait to be a mum and I know he's pushing to be a dad. We've been thinking about (having a baby), but I think it's going to happen when everything is more settled."
Jonas is currently in the midst of a summer (13) tour of the U.S. with his bandmate brothers Nick and Joe.