Doctor Who star Elisabeth Sladen has died aged 63.
No details have been released by her agent but BBC entertainment correspondent Lizo Mzimba told BBC News that: "She'd been suffering from cancer for some time."
Her most famous role was in Doctor Who as journalist Sarah Jane Smith who was originally a companion to Jon Pertwee, the Third Doctor. She continued with Tom Baker, the Fourth for a total of three years from 1973 to 1976.
The character was so popular that in 1981 she was cast in the show's first spin-off, the unsuccessful K-9 and Company. Russell T Davies brought her back to join David Tennant's Tenth Doctor and then created a new spin-off show for her, The Sarah Jane Adventures which has run since 2007. Last year, Matt Smith's Eleventh Doctor guest-starred in an episode with her.
Russell T Davies said: "It's devastating - that's no age at all, is it? All of us who worked on Doctor Who and Sarah Jane Adventures are reeling at the moment. There are a lot of children who are going to need hugs from mum and dad when they wake up in the morning and hear the news. It's just so sad."
In 2010, readers of RadioTimes.com voted her the second most popular Doctor Who companion ever, beaten only by Billie Piper as Rose Tyler.
She leaves a husband and daughter.