One of Star Trek: Discovery's biggest mysteries just got one step closer to being revealed.

TrekMovie.com revealed that Vampire Diariesalum Mia Kirshner will be joining Discovery as Amanda Grayson — known better to Trekkers as Spock's mom. Amanda was previously played by Jane Wyatt in The Original Series and Winona Ryder in the 2009 Star Trek film.

This is crucial information because Discovery centers on disgraced First Officer Michael Burnham (Sonequa Martin-Green), who became the ward of Amanda and her Vulcan husband Sarek (James Frain) after Klingons killed her parents. When it was announced that Michael was raised by Vulcans — specifically Sarek and Amanda — the Trek universe began to buzz. How could Spock have an adopted sister that he's never spoken of?

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So far, Discovery has only mentioned Spock once. In Episode 3 Michael says her adopted mom (Amanda) used to tell her a story but her adopted brother didn't participate. That's all we know about their relationship at this point. Executive producer Alex Kurtzman has promised that the reason Spock has never talked about Michael will be revealed — and Amanda joining Discovery could be a huge part of that.

The question now is: Will Amanda's appearance also mean the possibility of a Spock cameo as well? Executive producers have been tight lipped about the possibility, but wouldn't it make an awesome Season 1 twist?

Star Trek: Discovery new episodes arrive every Sunday at 8:30/7:30c on CBS All Access.

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