Personnel details for the upcoming third series of ‘The Crown’ are emerging, with the Netflix-based show officially adding Helena Bonham Carter and Jason Watkins to the cast.

It had already been known for some time that the main stars of the first two highly successful series – Claire Foy and Matt Smith as the Queen and Prince Phillip – were being replaced by Olivia Colman and Tobias Menzies. Bonham Carter’s prospective role as Princess Margaret had been rumoured as long ago as January, but has only just been officially confirmed this week.

“I'm not sure which I'm more terrified about - doing justice to the real Princess Margaret or following in the shoes of Vanessa Kirby. The only thing I can guarantee is that I'll be shorter than Vanessa,” the 51 year old British actress and former BAFTA winner said on Twitter on Thursday (May 3rd).

Helena Bonham CarterHelena Bonham Carter is to join 'The Crown' for season 3

Another noteworthy addition to the cast is Jason Watkins, another BAFTA winner for his lead role in the TV drama ‘The Lost Honour of Christopher Jeffries’, who will play the Labour prime minister Harold Wilson.

More: Claire Foy responds to being paid less than Matt Smith on ‘The Crown’

“I am delighted to become part of this exceptional show. Harold Wilson is a significant and fascinating character in our history. So looking forward to bringing him to life, through a decade that transformed us culturally and politically. And excited to be working so closely with Olivia and the whole team,” Watkins said in his own statement.

When ‘The Crown’ resumes for its third season – predicted to be at some point in 2019 – there will be a time-jump from where it left off in the 1960s. Season three will deal with Harold Wilson’s premiership in the mid-Seventies.

Recently, ‘The Crown’ was the subject of a gender pay-gap controversy, with Claire Foy reported to have earned less than her co-star Matt Smith. The production company has since apologised, and Foy is to receive back pay to level up her earnings with Smith’s.

More: Claire Foy admits she initially feared ‘The Crown’ wouldn’t be popular