Joan Watson's mom is coming to town on Elementary.

Everwood vet Freda Foh Shen will play Mary Watson, Joan's (Lucy Liu) disapproving mom, in the ninth episode of the season, TVLine reports. Slated to air on Dec. 13, the episode will see the meeting of mom and Sherlock (Jonny Lee Miller). "Given what we know about mom — or heard about mom — and given what we know for sure about Sherlock, you can see it going a certain way. I feel like we're going to tell a story with a few lovely, little surprises," executive producer Rob Doherty told the site.

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Foh Shen played Dr. Chao on Everwood, and also recurred on Close to Home and Gideon's Crossing in recent years.

Elementaryairs Thursdays at 10/9c on CBS.

Are you excited to meet Watson's mom?