"It's so rewarding to see the smile on these kids faces," Richie, 28, tells PEOPLE.
Several of the pint-sized inhabitants of Beyond Shelter's Broadway Village 2, a shelter in an L.A. neighborhood with the highest concentration of crime and poverty, turned out to celebrate the happy news that they would soon have a place to play.
"I spend tons of time here," says Richie. "When I found out the kids play on a concrete slab or play inside all day, it hit me. Kids need to have an imagination, to be outside and to be free."
So will they soon be having play dates with Harlow? "Absolutely," says her proud dad, 30. "Now that she's playground age, she can!" Adds Richie, "We started [the Richie-Madden Children's Foundation] so it could be something that our siblings, parents and our kids could all do together. It's something we talk to her about all the time."
Next up for the couple, who raised $35,000 for the playground with the help of C&C California and Marble Slab Creamery, is 4EveryBaby, an online baby registry for mothers in need.
Madden jokes that with all the projects Harlow has inspired, including Richie's jewelry line House of Harlow 1960, the couple are brainstorming a project in Sparrow's honor. "Sparrow's going to get an awesome club," he quipped. "Because he's awesome."
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