While Whovians are preparing for companion Clara Oswald's departure from "Doctor Who," executive producer warns fans that this might truly be the last farewell for the character.

In an interview with Movieplayer, Moffat previewed Clara's upcoming exit during the "Doctor Who" Season 9 finale.

"Clara is gone and will never return," he said. "I will not reveal any forecast about her fate. I can only say that what will happen will shock, terrify and surprise. Strictly in that order."

While the "Doctor Who" revival has given way to many returns for iconic characters like Rose Tyler (and previous generations of the Doctor), Moffat seems to be suggesting that Clara will never make a cameo again. However, some observers were quick to point out that Moffat only spoke on the character and now actress Jenna Coleman.

But the same could not be said for fan-favorite River Song, who is slated to make a return to the franchise during the "Doctor Who" Christmas Special.

"As for River Song, well, I was very, very tired," said Moffat according to Doctor Who TV. "It was the end of the season and I did not know if I would be back for another year, so I wondered what I would do if that was my final 'Who' episode. I like to write to [River] and even Russell [T. Davies] told me a long time [ago] that I should bring [her back]. That's why I brought her in the series, because it could have been the end."

While Clara may be gone forever, Moffat reassured fans that Peter Capaldi "is going nowhere" as the Doctor for Season 10.