So is missy an old friend?

I think that could very well be the twist we have not actually seen her do anything bad she has talked to a few dead people some who were bad but others who were good and have a hint she picked Clara.

Agreed we heard her have a sort of evil laugh but that is it

If it's old friends from previous episodes this series I predict:

Journey Blue
Robin Hood
Courtney
Psi
Salibra
Lundvik
Maybe Perkins?
Rigsy

I'm sticking with UNIT. I don't think it's meant to mean anything more than that.

Not really old?

Maybe the Doctor will age over 1000 years in between this week's episode and the finale... Then they'll be "old" friends...!!!

(I don't genuinely think that will happen, but wouldn't put it past Moffat to do that... Again)

They're in the past though.

It's not gonna be Martha, Donna, Ace etc is it?

Kate and Osgood, with the enemy being the Cybermen.

Can't see it being more than that.

Also K9.

Will be nice to see kate again. Anything else would be a nice bonus. If not maybe S9 can see the return of more old freinds and villians ?.

So will the Doctor take on the role of a woman in this one?
That might shock a few people, but its well within the range of Capaldi's acting skills!

What? Where has this idea come from?
I can see no reason at all why the Doctor 'would take on the role of a woman.'
I presume you have something specific in mind?
Otherwise it's a very random suggestion - you might as well say 'will the Doctor take on the role of a penguin in this one?'

That could happen, Capaldi could be Frobisher disguised as The Doctor

(6's companion Frobisher, not John Frobisher)

I know it's highly unlikely but it would be great if Jo Grant was in it. After all, she was photographed with Peter Capaldi on set not so long ago.

Surely acquaintances rather than old friends.

This finale has been made out to sound like 'THE final battle'. Sacrifices are to be made, old friends reunite against old enemies in London. I think whatever happens, we are in for two seriously cracking episodes.

As long as k9 is not killed off im happy.

But with Moffat playing with 'time can be rewritten' again in the trailer it probably won't matter what happens I them because judging by his past efforts I wouldn't be surprised if by the end no one will have died and the whole thing will never have happened at all.

Sounds like the same finale synopsis we get every year to me!

Kate Stewart and Osgood. It's been 900 years for him since he last saw them.

Moff is going to write some big plot and then completly re write the thing in the last 5 minutes with a "times been rewrittern" as per where the past 2 weeks didnt even exist! :/

I smell a regeneration.

Maybe in about 7-10 years with any luck he'll last at least that long