AceShowbiz - Helena Bonham Carter isn't convinced she bears much of a resemblance to Queen Elizabeth II's sister, who she will portray in the third season of Netflix show "The Crown".

The actress has been drafted in to take over the role of Princess Margaret for the next series, which hasn't yet begun filming.

And she confided that as well as being excited, she is slightly "terrified" at the prospect.

Her predecessor Vanessa Kirby, who portrayed Margaret in seasons one and two which focused on the inner-workings of the royals during the early days of Elizabeth II's reign, was praised for her likeness to the party princess. However, Helena isn't so sure she bears much of a resemblance to the Queen's sibling.

"None of us look at all like our previous generation," the 52-year-old actress insisted in a chat with Variety on the red carpet of the "Ocean's 8" premiere. "We don't actually look like our real people either. I don't look like Margaret. I don't think Olivia (Colman) looks particularly like the Queen, but it's interesting."

For season three, Helena is one of a number of actors who have been hired to join the Golden Globe award-winning cast, including Broadchurch star Olivia, who will replace Claire Foy as the British monarch, as the production plans to make a significant time jump, which required recasting the show with an older group of actors.

"We just have to try and create some sort of essence," mused the actress. "The good thing is that all the characters are so multifaceted, so we will probably capture different bits."