British actress Helen McCrory fears she has scarred her kids for life after they were left terrified by her appearance on the set of new film Bill.

The Harry Potter actress portrays Queen Elizabeth I in the new family movie about the real life of William Shakespeare.

Rather than the flame-haired monarch usually shown on screen, MCCrory underwent a drastic transformation for the role, wearing a bald cap and using make-up to create smallpox scars.

But her look backfired when her children Manon and Gulliver visited the set - and she fears she is the reason for their recent nightmares.

MCCrory tells London's Evening Standard, "My children recently came on set to watch me play Elizabeth I in an upcoming film. I warned them I decided to play her as she really looked, with pockmarked skin and bald, but occasionally they wake up in the night whimpering and I wonder if it's because of that image."