"My first fashion show ever!!! Starting at the top with this one @gigihadid leading the pack!!! It was amazing and so was she!!! #proudstepdad #versace," Foster captioned a photo of his stepdaughter.
Yolanda Foster also showed her support for Hadid on Instagram, writing, "#ProudMommy #WatchingFromAfar." The 52-year-old reality star is also mom to daughter Bella and son Anwar, and called her kids "the best thing" to ever happen to her in a post Saturday.
Foster and Yolanda Foster were together for nine years, and announced their split in December after four years of marriage. The musician is reportedly still paying for his estranged wife's Lyme disease treatment, and defended her to critics following their breakup.
"I have always had and continue to have the utmost respect and love for Yolanda, which is why it is so frustrating to see headlines questioning her chronic debilitating illness," he told Us Weekly.
Yolanda Foster shares Gigi, Bella and Anwar with her first husband, and previously told People she is leaning on her children during her divorce and continuing struggle with Lyme disease. Hadid won $25,000 on MasterChef Showdown for Global Lyme Alliance this month.
"I'm the only one in, of my siblings, my mom and my family, that hasn't been affected by Lyme disease," the model told Entertainment Tonight in October. "What's been hardest for me is just trying to find a way to be their hope and kind of be a strength for them."
Hadid is known for her modeling work with Guess, and walked in her first Victoria's Secret Fashion Show in November. She is presently dating Zayn Malik, and was recently spotted apartment hunting with the former One Direction singer.