Helena Bonham Carter is ''completely terrified'' of working on 'The Crown'.

The 52-year-old actress is set to take over from Vanessa Kirby as Princess Margaret in the upcoming third season of the Netflix drama and she admitted she and her co-stars Olivia Colman and Tobias Menzies - who will replace Claire Foy and Matt Smith as Queen Elizabeth and Prince Philip - are feeling the pressure of joining such a successful series and having to make the parts their own.

She told Variety: ''I've definitely started prepping. It's exciting.

''We start in a few weeks, and I think we're all -- we're completely terrified.

''I think also because the first two seasons were such a success, we have the onus of inheriting the responsibility of doing justice to all these genuinely famous people, and then on top of it, inheriting them from this previous generation of actors who've done such good jobs.''

Though Helena admits she doesn't look anything like either Vanessa or Margaret - who died in 2002 aged 71 - she doesn't think that's important so long as she can capture the ''essence'' of the princess.

She said: ''None of us look at all like our previous generation.

''We don't actually look like our real people either. I don't look like Margaret. I don't think Olivia looks particularly like the Queen, but it's interesting. We just have to try and create some sort of essence.

''The good thing is that all the characters are so multifaceted, so we will probably capture different bits.''

Season three of 'The Crown' will begin filming in the UK later this summer.