The tennis champion, 35, shared footage from their outing in a Snapchat video on Thursday, September 28. Williams appeared to be wearing a casual strapless white dress while the Reddit cofounder wore shorts and a black shirt.
"We miss her already," she captioned the clip. She later said: "We miss Olympia."
Earlier in the day, the new mom showed off her post-baby body in a mirror selfie.
Williams shared the first photo of her newborn on September 13. "So we’re leaving the hospital after 6 days, it’s been a long time," Williams said in a video at the time. "We had a lot of complications but look who we got! We got a baby girl."
The star previously opened up about motherhood and her pregnancy in an interview with Vogue. "This pregnancy was unexpected and accidental. But once I found out, something happened that surprised me, I became really calm," she said. "The one thing I really want is an epidural, which I know a lot of people are against, but I’ve had surgeries galore, and I don’t need to experience any more pain if I can avoid it. But the biggest thing is that I don’t really think I’m a baby person. Not yet. That’s something I have to work on. I’m so used to me-me-me, taking care of my health, my body, my career. I always ask, am I going to be good enough?"
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