I think I got it because I was so sure I wouldn't that I was really extremely relaxed about it. I know an awful lot of people were up for the part, and it was a frightfully prestigious thing to get. We did it in a break between my two series of Doctor Who so I went along for the audition and thought, 'You must be joking, they're never going to give this to the Doctor Who girl.'

I think it was because Cedric Messina, the producer, had probably never even heard of Doctor Who, certainly never watched it that I got away with it. Perhaps because I was relaxed I did a good job at the interview for not being petrified out of my skin, so I got it.

Then I went to the read-through. I'd been watching on telly a series that they did on Sunday evenings of Shakespearean actors showing you how to perform, how to read sonnets, and one of them was Patrick Stewart, who played Claudius in that Hamlet. I was terrified of him because he was so good in this programme.

Claire Bloom who played Gertrude wasn't there because she was still doing Brideshead, which went on interminably because of strikes - probably the same strike that clobbered Shada got her - so she wasn't there. There are only two women in Hamlet, Gertrude and Ophelia so mine in a four hour read-through was the only female voice to be heard, since our script editor decided to read in Gertrude. He did a jolly good job actually.

Every time I opened my mouth I sounded like a little mouse. It was so scary and awful and I'd learnt the songs, which are frightening to do, two days before, so I kept thinking 'Oh my god, what am I going to do? This scene's going to turn up and I'm going to have to do these songs and oh god help.'

At the beginning somebody, I suppose the director, had said 'I'm sure every one of you has played parts in Hamlet in the past,' and Eric Porter, who was playing Polonius said, 'Well, as a matter of fact I've never been in Hamlet.' I thought, 'Oh goody, someone else who's never done this sort of stuff.' [Then] he said 'I've been in 30 of the 32 plays, of course, but funnily enough never Hamlet.'

I thought, 'Well there goes my ally in this thing. And then after the read-through I went down in the lift with Patrick, and he said 'Gosh, that was a marathon, wasn't it,' and I said 'Yes,' and he said 'Of course the highlight was the songs, that was wonderful.' I thought, 'Oh, thank you that was all right then.'

Patrick said to me, 'You used to be in Doctor Who didn't you?' and I said 'Yes, I still am actually,' and he said 'I mean why do you do all this television, why don't you do proper stuff like theatre,' and I said 'Well I love it actually, I love doing Doctor Who.' 'But science fiction, I mean why would you want to do science fiction?' I said, 'I don't know - I think partly because you learn so much technical stuff, it's really interesting,' and he said 'Oh I wouldn't want to do that sort of stuff.'

I haven't run into Patrick Stewart since, but I look forward to it so I can say, 'Funny, why do you do all that sort of science fiction stuff you do now, why aren't you doing the proper theatre like real actors.'