Billie Piper, Freema Agyeman, Catherine Tate and John Simm will all appear in David Tennant's last episode of Doctor Who, it has been claimed.
Simm is said to be in line to reprise his role as The Master, while Piper, Agyeman and Tate will join forces as companions Rose Tyler, Martha Jones and Donna Noble, The Sun reports.
The episode will also see The Doctor regenerate, with Tennant being replaced by Eleventh Doctor Matt Smith.
An insider said: "This will be the most exciting episode Doctor Who have ever done. We really wanted to get all the companions back on board as a fitting send-off to David.
"And of all the enemies for him to face in his final episode, it makes sense for The Master to be the main one.
"Getting Billie to agree is a real coup, but she loved working on the show so much it didn't take much convincing."
Tennant is due to play The Doctor in four specials during 2009 before he leaves the show, while Steven Moffat will replace Russell T. Davies as executive producer and head writer in 2010.
I don't think it's been confirmed yet, but it's certainly on the cards.
As much as I would love to see this, I kinda expected this may happen on Tennants final episode