I’m not sure this is totally surprising news, because there were rumors that Jenna Coleman had planned to leave Doctor Who during the Christmas special last year (in fact, I believe, she equivocated right up until the very end, and Moffat had to write two endings, depending on what decision she arrived at).
Now, however, it seems that she really is leaving Who, having signed on to star in the upcoming series, Victoria, where she’ll play Queen Victoria, so reports The Guardian.
Nevertheless, with three years under her belt, Coleman — who plays Clara Oswald — is still somehow the longest serving companion on the modern series, thus far. She will have surpassed Karen Gillan by the end of this season’s run (the last two episodes of the season, by the by, will likely not feature Coleman’s character, according to some reports. She is not expected in the Christmas special, either).
She’ll be missed. After Billie Piper, she is personally my favorite of the modern Who companions.
via The Guardian