Jana Kramer Pregnant, Expecting Baby With Fiancé Allan Russell

Jana Kramer is adding a new member to her family! The country singer, 39, is expecting her first child with fiancé Allan Russell, she announced Thursday on social media. Sharing a photo with Russell — to whom she announced her engagement last month — and her positive pregnancy test, the One Tree Hill alum confessed she had been "keeping another secret" from her followers for a while.

"Beyond blessed and grateful for this baby to be a part of our story," wrote Kramer, who is also mom to daughter Jolie, 7, and son Jace, 4, with her ex-husband Mike Caussin, admitting she "never thought [she] would see the word pregnant again" on a pregnancy test. The "I Got the Boy" singer reiterated her shock at this pregnancy to PEOPLE, saying she "didn't think it would ever happen again, if I'm being honest."

"I've been through a lot, so this has just been a really beautiful thing," she continued. "I'm letting it all sink in. It's everything I've wanted and more. Allan was so sweet. He wrote me this little sticky note saying, 'You deserve the happy ending.'" Kramer and Russell, who has a 16-year-old son from a previous relationship, began talking about expanding their family earlier this year.

"I've had miscarriages, so I didn't even know if it was possible. I'm like, yes, it'd be beautiful for us to create something because I love this man. It would be the silver lining with everything that happened, but I'd always get kind of down about it because I didn't know if I was capable of carrying a pregnancy again," she said. "I was like, well, I'm going to be 40 in December, so I was like, we have one month to try. Literally one month."

In March, during a trip to Los Angeles to attend the iHeartRadio Music Awards, Kramer realized she had the same "metallic taste" in her mouth that she had with her previous pregnancies, prompting her to take a pregnancy test. After "crying" at the positive result, Kramer shared the big news with daughter Jolie in May, who is "so happy" to be welcoming another sibling.

Now that she's made it out of the first trimester, Kramer said she's leaning into the joy of her experience. "I was sick with Jolie and I had hyperemesis gravidarum with Jace. I've been sick with this one but not as sick as the last two," she revealed. "In the beginning of this pregnancy, I was bleeding a lot. It was scary, and I went to the doctor like, 'I've miscarried.' I actually had a large hemorrhage, so they'd have to monitor me, which has been kind of great because I've gotten to see the baby so much. Everything's good now, thank goodness."