CHICAGO — If Beyonce has said it once, she's said it a thousand times: If you like it, then you should have put a ring on it.
And on Sunday afternoon, that's exactly what Brad Fowler did for long-time girlfriend Alexandra Courtney outside the Adler Planetarium.
The couple met and started dating in 2006 while still in high school and kept their relationship going through long distances and college, Courtney said.
"Ten years, three apartments and a dog later, we are engaged," Courtney said.
The surprise began when Courtney's mom came to town Sunday to celebrate her birthday and requested a trip to the planetarium after dinner.
The group took a few family photos against the city's famous skyline in the background before Courtney said she was ushered to a plaza in front of the building where three dancers were cutting a rug to Beyonce's "Single Ladies."
Shortly after, the dance morphed into Bruno Mars' "Marry You" and Courtney said she slowly began to recognize some of the dancers.
Fowler had recruited dancers from his mom's Beth Fowler School of Dance to surprise Courtney before joining the mob itself and proposing to Courtney in front of dozens of friends and family.
"He knew I wanted all our family and friends there, but I never thought he would pull together a flash mob in one of the prettiest spots in Chicago, all without me knowing anything," Courtney said. "When I turned around to see everyone I was shocked to see so many faces I knew and so many that came from far away to be there. It was so special to have everyone there."
Courtney said having been engaged for only a day, the pair isn't yet sure when they'll officially tie the knot, but know it will be in the city where they've lived and loved for most of their relationship.
"We do know it will be in Chicago somewhere," she said. "We love this city."
Watch the full performance below.
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