Ashlee Simpson gave fans a glimpse of her "fun" family outing this week.
"Fun family Sunday at universal city walk," she captioned a photo on Instagram.
Simpson shares Bronx with ex-husband Pete Wentz, and welcomed Jagger with Ross in July 2015.
"Knox is such a good older brother," she told E! News in October 2015 after Jagger's birth. "He's always saying how beautiful she is and wanting to hold her."
"He's like a professional big brother, and he's got it down: He can calm her down and tell her it's okay, entertain her and dance with her," the star said.
"It's been such a long time [since I raised Bronx]. So maybe my age makes it a little different and, now having Bronx around, I have kind of a team," she mused. "It's nice."