"I took a pregnancy test and it was positive!" the singer, 36, tells PEOPLE. "It was so hard to keep it a secret. I was worried I'd start throwing up on set and everyone would be like, 'Oh, she's pregnant.' "
Now in her second trimester, Jewel and her husband, rodeo star Ty Murray, are finally ready to share their happy news.
The couple, who wed in the Bahamas in 2008, had been trying to have a baby for two years. "I have always been a workaholic, so I had to learn how to slow down and take care of myself in a different way," Jewel says about her struggle to conceive.
Jewel and Murray, who live on a 2,200-acre ranch in Texas, are currently remodeling their home and converting the guest room into a nursery.
"I'm trying to be in the moment and really enjoy my pregnancy," says the singer, who in 2009 released a collection of children's songs titled Lullaby and is now working on a new children's album. "I feel really lucky."
For more on Jewel and Ty, pick up the new issue of PEOPLE, on newsstands Friday