Dr. Kai Bartley, played by non-binary actor E.R. Fightmaster, made their debut on Season 18’s third episode as a Parkinson’s disease researcher.

Dr. Meredith Grey and Dr. Amelia Shepherd meet Dr. Bartley while on a trip to the Minnesota hospital where they work. When the show picks back up on November 11, Dr. Bartley will return as a regular on the long-running medical drama.

ABC describes Dr. Bartley as “dedicated to their craft and extremely talented at what they do,” as well as “confident as hell and able to make even the most detailed and mundane science seem exciting and cool.”

Last week, Fightmaster celebrated the news of their casting on Instagram, posting a headline from Variety and writing, “I am having so much fun.”

The official Grey’s Anatomy Twitter account also posted the news and wrote that Fightmaster “has been an incredible addition to the #GreysAnatomy family.”

In addition to playing the show’s first non-binary doctor, Fightmaster appears to be the first non-binary actor who has been out while appearing on the show. Sara Ramirez, who played Dr. Callie Torres from 2006 to 2016, came out as non-binary last year.

Trans actor Alex Blue Davis also played trans doctor Casey Parker for three seasons.

Many fans have expressed their excitement to see Fightmaster on the show, as well as their theories about what they have deemed the obvious chemistry between Dr. Bartley and Dr. Amelia Shepherd.

Fightmaster graduated from DePaul University and is an alum of Chicago’s renowned Second City comedy club. They have appeared in the Hulu series Shrill, as well as Showtime’s Work in Progress.