Los Angeles, California - Millie Bobby Brown dropped a bit of a bombshell as she casually revealed her famous moniker isn't her real name!

During an interview with Buzzfeed promoting her new movie The Electric State, the 21-year-old revealed to co-star Chris Pratt that her famous middle name was made up.

"It's not Bobby. It's Millie Bonnie Brown," she said.

A visibly shocked Chris asked, "Really?" as Millie admitted, "I've never told anyone that. You heard it here first."

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The 45-year-old Marvel star then asked why she made the swap for her stage name.

As it turns out, Millie doesn't exactly have any special reason for doing so, responding, "For s**ts and giggles."

Despite her quip, the name wasn't exactly random, as it's a tribute to her dad, whose name is Robert.

While the Enola Holmes star appeared to make the swap when she began acting at the age of nine, she has made another big name change as an adult after getting hitched to Jake Bongiovi last year.

Millie adopted her hubby's last name, revealing in a post from the set of Stranger Things that her name was now listed as the extra-alliterative "Millie Bobby Brown Bongiovi" – though she seems to be sticking to her original stage name professionally.