Ashlee Simpson is still daddy's little girl.
As her and older sister Jessica Simpson's father Joe Simpson celebrates his birthday on Saturday, the singer took to Instagram with a heartwarming message and photo of the duo.
"Happy Birthday Daddy your my sunshine I love you sooooooo very much," Simpson captioned a snapshot of herself kissing Joe on the forehead, who flashes a silly face for the camera.
The talent manager-turned-photographer is currently facing a battle against prostate cancer, a disease he was diagnosed with last September. News of Simpson's health scare broke two months later, and at the time, he had undergone prostate surgery and returned to work.
Over the holiday season, Joe celebrated Christmas with Jessica and her family, taking to Instagram to share he was "so thankful for my many blessings."
Most recently, Us Weekly reported the 59-year-old had started radiation treatment, and is hopeful for a positive outcome. "He feels fine, he's getting through it and still working. It's all scheduled once a week. He's super optimistic," a source shared with the outlet.
Additionally, their insider revealed Joe, Ashlee and Jessica have grown "closer because of what he's going through."
"[Ashlee and Jessica are] so professional. They're so good and they know how to work a camera," Joe gushed to E! News' Erin Lim last May. "They know their stuff."
He continued, "Their joy makes me happy. As a father, it's not what your children do. It's who your children are and are they happy? That's the question you'll always ask."