0:00:02 > 0:00:04'This week, the Doctor faces his biggest threat to date,
0:00:04 > 0:00:06'in the alliance to match all alliances.'
0:00:06 > 0:00:10- This episode has to say "big". - Listen to me!
0:00:10 > 0:00:13We're turning it up to 11, we are really going mad with this one.
0:00:14 > 0:00:20'And Confidential gees up for a journey with a difference.'
0:00:20 > 0:00:21Ha-ha-ha!
0:00:21 > 0:00:24It's hilarious! What a funny little gesture.
0:00:24 > 0:00:27He probably worked harder than Alex and I.
0:00:56 > 0:01:00Down on set, the Doctor Who cast and crew are preparing for a climactic cliff-hanger.
0:01:00 > 0:01:04Just let him pull you a bit, with your arms behind you. Throw you that way.
0:01:04 > 0:01:07This is the Doctor being shoved into the Pandorica,
0:01:07 > 0:01:09where he's going to be imprisoned.
0:01:09 > 0:01:12Effectively, it's the death of the Doctor.
0:01:12 > 0:01:13Or the Doctor that we know.
0:01:13 > 0:01:17We hold like this, and then if you take your weight, and I'll swing like that.
0:01:19 > 0:01:21So we've got all the monsters out here.
0:01:21 > 0:01:23This is the first time we've had Cybermen
0:01:23 > 0:01:28and Daleks and Sontarans all together in one big thing.
0:01:28 > 0:01:31It's like a big classic Doctor Who cliff-hanger.
0:01:31 > 0:01:34We've got to go into this thinking it's all over for the Doctor,
0:01:34 > 0:01:36and how is it going to get out? It's doom for him.
0:01:36 > 0:01:42Off we go then. Rehearsing, and action!
0:01:42 > 0:01:45HE SHOUTS
0:01:55 > 0:02:01Time for the ultimate alien alliance to get suited and booted ready to take on the Doctor.
0:02:18 > 0:02:23We've done pretty well so far. We've got first ADs trained in all the alien languages.
0:02:24 > 0:02:30We've got people who speak pure Dalek and Sontaran translators out there.
0:02:30 > 0:02:32We're marshalling them quite well I think.
0:02:32 > 0:02:33Camera!
0:02:33 > 0:02:39It's really exciting to have such legendary characters together,
0:02:39 > 0:02:41Daleks and Sontarans in the same frame.
0:02:41 > 0:02:44You've got Cybermen and Weevils and all these kind of things.
0:02:44 > 0:02:47That's what we've never really seen in Doctor Who before,
0:02:47 > 0:02:51these creatures side by side, working together,
0:02:51 > 0:02:55like some sort of terrible alliance.
0:02:55 > 0:02:57And cut there, brilliant. OK.
0:02:57 > 0:03:00I'm really excited. We've just got to get all the shots in.
0:03:14 > 0:03:16Action!
0:03:16 > 0:03:20- DALEK:- You have been scanned,
0:03:20 > 0:03:23assessed, understood.
0:03:23 > 0:03:25The Pandorica is ready!
0:03:25 > 0:03:30- Ready for what? DALEK:- Ready for you.
0:03:37 > 0:03:41I think I'm most impressed with the Sontarans.
0:03:41 > 0:03:45When you just see them in front of you moving and talking,
0:03:45 > 0:03:48he really does seem like a real creature, and he's really quite scary.
0:03:48 > 0:03:51He looks quite fierce, and directing him is kinda weird,
0:03:51 > 0:03:56he's constantly looking really angry but it's just his make-up.
0:03:57 > 0:04:00- The Pandorica is ready. - Ready for what?
0:04:00 > 0:04:03- DALEK:- Ready for you.
0:04:03 > 0:04:05It's great, seeing all the monsters together.
0:04:05 > 0:04:09The seven-year-old child inside me kind of goes, "Oh, my goodness!"
0:04:18 > 0:04:22- Seal the Pandorica.- No! Please!
0:04:22 > 0:04:25The whole universe will never have existed.
0:04:25 > 0:04:30Please listen to me! Get me out of this chair, listen to me!
0:04:33 > 0:04:37- Cut!- The alien coalition has won.
0:04:37 > 0:04:40After 907 years, the Doctor's fate looks sealed.
0:04:44 > 0:04:49With the crew's saddlebags packed, it's a trek up the Trefil Mountains
0:04:49 > 0:04:55to create the epic journey to one of the oldest locations used on Doctor Who, Stonehenge.
0:04:55 > 0:04:58To get there, Matt, Karen and Alex have to take a back seat
0:04:58 > 0:05:02and let three lookalike stunt riders take up the reins.
0:05:02 > 0:05:05I loved filming the horses - it made the whole thing more epic.
0:05:05 > 0:05:08We wanted to give it this big adventure feel.
0:05:08 > 0:05:14And we intercut it with these horse shots, which were River, the Doctor and Amy riding their horses along
0:05:14 > 0:05:18which is technically quite difficult to achieve, mainly because
0:05:18 > 0:05:21you can't have the real actors actually riding the horses.
0:05:21 > 0:05:26You need to have stunt doubles, and stunt doubles never look like
0:05:26 > 0:05:29the actors, they just look like people in wigs.
0:05:31 > 0:05:34We shot some wide shots of the horses just riding along,
0:05:34 > 0:05:39and tried to make those as dramatic and impressive as possible.
0:05:39 > 0:05:44The trick of it really is to make sure that there's enough energy in the shot to take your eye away
0:05:44 > 0:05:50from what the trick of it is, that they aren't really Matt and Karen riding those horses.
0:05:50 > 0:05:53MUSIC: GALLOPING HOME
0:06:02 > 0:06:06To find a stretch of land that a horse could run on,
0:06:06 > 0:06:11and a car could drive next to it on a straight bit of road, was quite a difficult thing to do.
0:06:11 > 0:06:16This is supposed to be ancient Earth, you know, the time of Stonehenge and the Romans.
0:06:16 > 0:06:21Obviously we didn't want any pylons or cottages or any buildings in the background at all.
0:06:26 > 0:06:30With the stunt riders making sure the filming didn't fall at the first fence,
0:06:30 > 0:06:34it's time for the actors to mount up and face a few hurdles of their own.
0:06:34 > 0:06:42We got Matt and Karen and Alex on the back of a truck, and made them do sort of horsy positions.
0:06:58 > 0:07:00It kills your thighs!
0:07:00 > 0:07:04For camera they want you to sort of go quicker and faster,
0:07:04 > 0:07:10but you have to think about the horse, and how the horse rolls.
0:07:10 > 0:07:11It doesn't just go like that.
0:07:11 > 0:07:16I had to pretend to be riding a horse on this seat on the back of a truck.
0:07:16 > 0:07:20And then they drove the truck and I just had pretend that I was on the horse.
0:07:20 > 0:07:24Toby kind of demonstrated the bouncing action that he wanted me to do.
0:07:24 > 0:07:28A bit faster. As if it's going "Brrm-ba-dum, brrrm-ba-dum."
0:07:28 > 0:07:29And then he said,
0:07:29 > 0:07:32"Oh, do a serious look, as if you're kind of on a mission."
0:07:32 > 0:07:36And then one where I was having the time of my life, and then another one where
0:07:36 > 0:07:40I wasn't quite in control because I don't think Amy has ever ridden.
0:07:49 > 0:07:53That's possibly one of the strangest things I've ever done.
0:07:53 > 0:07:57Matt looked ridiculous, absolutely ridiculous!
0:07:57 > 0:08:00He really went for it, though, I'll give him that.
0:08:02 > 0:08:05Hilarious, what a funny little gesture.
0:08:05 > 0:08:08He probably worked harder than Alex and I.
0:08:15 > 0:08:18It's a little bit undignified. I didn't realise how undignified
0:08:18 > 0:08:21it looked until he did it, so I'm quite glad I went first.
0:08:24 > 0:08:27We just shook the camera around a bit, and cut it all together,
0:08:27 > 0:08:30and it looked like they were riding horses.
0:08:39 > 0:08:41It's quite hard work. Look, I'm puffed out.
0:08:41 > 0:08:44You're sort of having to use your legs,
0:08:44 > 0:08:47like this. I feel a bit of a berk doing it.
0:08:47 > 0:08:50It's a shame we couldn't ride a proper horse.
0:08:50 > 0:08:53Hopefully, it'll look good. The magic of film, you see?
0:08:57 > 0:09:01I'm going to go and keel over in the mud or something.
0:09:06 > 0:09:11Hya, come on! Hya! Hya! Hya!
0:09:26 > 0:09:30Subtitles by Red Bee Media Ltd
0:09:30 > 0:09:33E-mail subtitling@bbc.co.uk