Roger Moore's step-daughter has died of cancer aged 47.

Bond star Moore, who has been in a relationship with Christina Knudsen's mother Kiki Tholstrup for more than two decades, described his heartbreak over the death of "our daughter" in a photo tribute on Twitter.

The 88-year-old wrote: "Our beautiful daughter Christina (aka Flossie) lost her battle with cancer 25 July at 10am. We are heartbroken."

Knudsen, a 47-year-old socialite, told the Evening Standard in 2014 how her life changed for the better when her mother met Moore, following the death of her father from suicide when she was six and the death of her step-father from alcoholism.

London-based Knudsen was married to investment banker Nikolaj Albinus for 13 months before starting a long-term relationship with Skype co-founder Janus Friis.