Check Kim Kardashian faux pas at Tracee Ellis Ross birthday party

Kim Kardashian ended up in a full Mystique dress for Halloween at Tracee Ellis Ross’ pre-50th birthday celebrations in her Mystique dress, only to realize it was not a theme party, according to Page Six.

“That time I showed up to a birthday dinner in full costume when it wasn’t a costume party!” the reality star wrote in a selfie with the Black-ish star on her Instagram Story.

The cosmetic mogul sported her Mystique costume from the X-Men series, skin-tight bodysuit, red hair, and bright blue paint. Ross was also dressed in an adorable red get-up laced with diamonds.

“Happy Birthday to the most beautiful kind soul @traceellisross,” the 42-year-old captioned her tribute to the actress.

Later, The Keeping up with the Kardashian star went to a proper costume party with Diddy, who donned the infamous character of Heath Ledger‘s Joker from The Dark Knight. “Never broke character,” Kardashian wrote in an Instagram Story selfie with the rapper.