Carrie Underwood's Husband Mike Fisher Celebrates Son Jacob's Milestone With Hilarious Photo

Carrie Underwood and Mike Fisher's son, Jacob, turned four months old on May 21, with Fisher celebrating the occasion with a hilarious photo-shopped picture of the infant.

"Can't believe Jacob is 4 months today!" Fisher captioned the picture, which showed Jacob decked out as an old woman.

Underwood is currently on her Cry Pretty Tour 360, with Fisher joining her on the road, along with Jacob and his big brother, 4-year-old Isaiah. The "Southbound" singer admits she is fortunate to be able to travel full-time with her family.

"[Isaiah] was 11 months old when we started the last tour," Underwood told ABC News. "So it was very much like: do a little makeup, make him dinner, come back and do my hair, then get him ready for bed. So it was worlds colliding, but it was great. I'm so lucky I get to take my kids to work with me, and not everybody gets to do that."

Underwood has child care while she is touring, although she acknowledges she doesn't use them very much.

"It'll just all happen at once. I went on tour with Isaiah when he was eleven months old," Underwood told PopCulture.com and other media. "He was right there when we had our first show. And it was really hard. Obviously, I have help when I'm out there. Somebody's gotta watch my kid when I'm out on stage.

"But I'm really bad at utilizing that, which I think is good, too," she added. "Nobody ever got up with my kid in the middle of the night but me. And I'm proud of that."

Jacob is still far too young to understand what his famous mom does for a living, but Isaiah has been able to occasionally stay up to see some of Underwood's performance, which Fisher recently captured on Instagram.

"What a night!" Fisher captioned the photo earlier in the tour, showing Isaiah enjoying part of the concert. "This is Izzy's first tour show that he'll remember. He had a blast and kept yelling 'Mommy I love you' when she came close!! His mommy is a rock star on stage and off the stage. Touring with a 3 month old is brave to say the least but if anyone can do it she sure can!!... The pictures don't do it justice what a show!! [cry pretty tour]

Underwood also spoke out after the photo, expressing her gratitude that she could do her job while still being with her family.

"I'm the luckiest wife/mom in the whole wide world to have my boys in the audience watching me!" wrote the singer. "Love you!!!"

Photo Credit: Getty Images/Rick Diamond