"She's doing great!" Richie told Usmagazine.com at the opening of the Eli Broad Contemporary Art Museum in L.A. last night.
"Really great, thank you!" added the 26-year-old, who looked slim and rested in a pale-colored dress.
Madden — who donned sneakers with his tux at the black tie event, and stayed arm-in-arm with Richie — chimed in: "Yeah, she's good!"
The museum opening was just the first stop on the pair's date night. Afterward, they hit up Clive Davis' Pre-Grammy party at the Beverly Hilton Hotel ? but didn't stay for long.
"We have to get home!" Madden was overheard telling a friend at 11:40 p.m. "She [Harlow] only sleeps three hours at a time. She's with Grandma now, but if she wakes up..."