A Twitter user, Bria Madrid, recently posted a photo of herself with another girl at a Spice Girls concert in 1997.
"Found a picture when I was 5 at my first concert," Madrid wrote. "Took a picture with a girl dressed up as Baby Spice who I just realized now was @blakelively."
Blake Lively retweeted the image and wrote, "My secret is out."
She also re-posted the photo on Instagram and caught the attention of Baby Spice herself (real name Emma Bunton), who wrote: "So cute, you're rocking those...