Teyonah Parris was as surprised as you

All Teyonah Parris knew about her audition for WandaVision was it was Marvel—which was extra confusing for her since she got a script set in the 1970s. She didn’t even know who she would be playing. But she nailed the audition and told her agent it would be cool if the role was of grown-up Monica Rambeau from Captain Marvel. Good call.
https://gizmodo.com/monica-rambeau-was-wandavisions-real-hero-and-the-show-1846433688