Reports say Helena Bonham Carter is joining the upcoming seasons of Netflix series "The Crown."

The world-famous Bellatrix Lestrange from the "Harry Potter" franchise is said to be all but confirmed to play the older version of the Queen's sister Margaret in the most expensive series ever made.

Season 2 of "The Crown" premiered on Netflix last Dec. 8 to a huge success, just like its sequel did before it. The second installment explored the years 1956 to 1964, with a focus on Queen Elizabeth's (Claire Foy) struggles as a new head monarch.

It was a tough time, which came at the same period the British public was questioning the need for a monarch. Add to that the infamous love life of her husband Prince Philip (Matt Smith), who was reportedly hooking up with various women in his commonwealth tour.

For Princess Margaret (Vanessa Kirby), it was the start of the "great party," after she was forced to break off her wedding with divorcee Peter Townsend (Ben Miles). Instead, she weds photographer Tony Armstrong-Jones.

In season 3, reports say there will be a huge jump in the timeline, which means there would be a need to change the major casts.

It was earlier reported that for seasons 3 and 4, Olivia Colman is taking the crown from Foy, who has won a Golden Globe award and a Screen Actors Guild award for her work in the series. She has also been nominated as best actress in the Emmy.

Series creator Peter Morgan has always been honest about his intent to change the casts to better portray the characters as they age. No news yet on who will replace Smith as Prince Philip.

Reports say production for "The Crown" seasons 3 and 4 is already well under way, despite the lack of go signal from Netflix. "The Crown" season 3 is slated to premiere in 2019.

Meantime, Bonham Carter is starring as one of the thieves in the upcoming "Ocean's 8," which premieres on June 22.