Reports surfaced that Helena would take over the part of Princess Margaret, currently played by Vanessa Kirby, but now the actresses have seemingly confirmed the rumours.
The two-time Oscar nominee was said to be “all but confirmed” to sign up, but a new snap of the pair together looks to have sealed the news ahead of an official announcement.
Harry Potter star Helena is no stranger to playing royalty having starred as the Queen Mother in The King’s Speech and the title role in the 1986 film Lady Jane.
The 51-year-old also starred as Anne Boleyn in the 2003 ITV series Henry VIII, and while a fictional royal, the actress also played the Queen of Hearts in Tim Burton’s Alice in Wonderland film adaptions.
Vanessa teased fans by posting a photograph on her Instagram account alongside Helena with the caption: “Honoured @thecrownnetflix.”
While bosses have yet to make an official announcement, this picture is likely to convince fans of the Netflix series that the film star will indeed play Princess Margaret.
Vanessa portrayed the princess during her younger years for the first two series, but after a cast change for season three was confirmed, Helena looks apt to take on the role.
Show bosses have previously confirmed that as time elapses, the cast would be changing to reflect the royals’ ages.
The next series will pick up in the 1970s, according to Vanity Fair, and the Queen’s children are likely to play more of a pivotal role in season three.
In 2017 it was verified that actress Olivia Colman would be replacing Claire Foy as Queen Elizabeth II.
Season two wrapped up in 1964 with the birth of the Queen’s fourth and final child Prince Edward, with the third season picking up after this point as fans meet an older version of the monarch.
It is likely that the Queen and Prince Philip’s marriage will be explored as it was in the first two seasons.
The Crown producer Suzanne Mackie also confirmed earlier this year that viewers will meet a young Camilla Parker Bowles.
She explained: “Peter is already talking about the most wonderful things. We start meeting Camilla Parker Bowles in season three.
“We have to be honest, season three and four are being mapped out and the closer the history comes – I now can say, ‘I know exactly what I was feeling when that happened, I remember that and I remember this.’ That’s so exciting.
“But there’s a responsibility to it that you ought to do it properly and there’s where the weight comes, not from seven years but we’ve got to keep being great.”