Millie Bobby Brown Shows Off Toned Bod Modeling New Undies, on Video

Millie Bobby Brown is obsessed with her new bralette and boxer look, and we're sure you're gonna love it, too ... because it is crazy hot!

The 22-year-old British actress recorded an early morning video for fans before she was ready to put on her "big girl clothes," which -- lucky for us -- meant she did the whole video in her undies.