The 30-year-old Fashion Star mentor and hubby Joel Madden took Harlow, 4, and Sparrow, 2, Down Under for some up-close and personal time with the animals Wednesday.
Sparrow, looking adorable in sunglasses and a baseball cap, fed a giraffe, which his mom took quite a liking to.
"Thank you Taronga zoo for introducing me to the love of my life," Richie posted on her blog, along with a close-up shot of the giraffe.
Madden, 33, had a great time as well. "Thanks [Taronga] Zoo for [having] us today with the kids," he tweeted. "They are still buzzing from it. Can't get enough. We'll be back fo sho."
The Good Charlotte musician added, "Australia is the best place for kids bar none. Pretty amazing to see my kids loving it as much as I do. So happy they feel [at] home :)"