Lady Antebellum helped celebrate a very important 100th birthday today, but it wasn't the birthday of a historical figure or a celebrity. No, this was a birthday party for a cookie -- the Oreo, to be exact. The 'We Owned the Night' singers took the stage at the Grove in Los Angeles to perform in honor of the centennial birthday of America's favorite cookie. To add to the festivities, the opening act was a flash mob.

"We just had a flash mob open for us, first time that's ever happened," Charles Kelley told USA Today after the performance. Lady A performed a handful of their chart-topping songs and then led the audience in singing a rendition of 'Happy Birthday' to the Oreo. And don't think that the occasion made the cookie any less susceptible to consumption. On the contrary, the whole band and their enthusiastic crowd had their fair share of cookies and milk.

"I had three," said Dave Haywood. When asked how many she had enjoyed, Hillary Scott said, "Two or three." Then, Kelley added to Haywood's total tally, interjecting, "Dave's lying. He did 100 -- for the 100th birthday!"

Lady A made the stop in the middle of their Own the Night 2012 World Tour, which is taking them to Chicago, Ill. on Friday (March 9) and then to Omaha, Neb. Saturday night, with Darius Rucker and Thompson Square. The trio are currently up for five potential Academy of Country Music awards for categories like Vocal Group of the Year, Album of the Year, Video of the Year and Song of the Year.