Matt Smith was on This Morning, and gave a few hints about what to expect on this saturday's series 5 finale of Doctor Who, The Big Bang:
"There's an important character coming back, but I can't say who," he said. "But it is very significant - it's a cracker![Digital Spy]
"I watched it and was quite emotional probably because it was the end of the series and we'd worked so hard and we'd got there. I watched it with Karen [Gillan] and we were like, 'Woo hoo!'"
There are many who are speculating that this character is Omega, who was a Time Lord, and an important figure in the history of Gallifrey. He is as important as Rassilon (who recently appeared in The End of Time, played by Timothy Dalton) and is the co-founder of Time Lord society. You can go and read about him here.
If this is the character that's returning, there are theories or rather spoilers as to who may play him and you can go read up on it here.
Only one day to go!
How excited are you about the upcoming finale?