Jessica Simpson celebrated sister Ashlee Simpson's 33rd birthday this week.
"Ashlee- I'm so proud to be your sister," Jessica captioned a photo Tuesday of Ashlee and her kids, 8-year-old son Bronx and 2-year-old daughter Jagger.
"I have always wanted to be as cool as you," she added. "I have never been inspired by anyone more than you! I love you so much! Happy Birthday."
Ashlee shares Bronx with ex-husband Pete Wentz and Jagger with husband Evan Ross, whom she married in 2014.
The singer shared a picture Tuesday of Bronx's homemade birthday gift -- a canvas featuring cute compliments.
"Mom your eyes are like a green forest with a blue lake," the 8-year-old wrote. "Mom your the best mom and theres billions moms you should know that! Happy birthday I love you so much!"
Entertainment Tonight reported Ashlee celebrated her birthday with Evan, Jessica and the designer's husband, Eric Johnson, Saturday at Beauty & Essex in Los Angeles.
Jessica presented her sister with a Gucci-themed birthday cake.
"She was over the moon!" a source said of Ashlee.
Ashlee released the album Bittersweet World in 2008, and has since starred in "Chicago" on Broadway.