Elisabeth Sladen was known for playing Sarah Jane Smith in The Sarah Jane Adventures. But she was famous long before she arrived on CBBC...
Here she is in 1973 at BBC Television Centre. She's celebrating being cast as Doctor Who's assistant in the latest series of the hit TV show.
She played Sarah Jane Smith alongside Jon Pertwee as the Doctor. This episode was called The Time Warrior, and was broadcast in December 1973.
Lots of people have been paying tribute to Elisabeth, who died of cancer aged 63 on 19 April 2011.
She captured the nation's imagination as Sarah Jane Smith in Doctor Who, and battled all sorts of monsters on the show back in the 1970s.
She played Sarah Jane alongside the third and fourth doctors: Jon Pertwee and Tom Baker.
And of course she also starred with David Tennant in the more recent TV show. This picture is an episode called School Reunion, from the second series of Doctor Who.
Russell T Davies, the creator of The Sarah Jane Adventures, said: "I absolutely loved Lis. She was just simply wonderful. The universe was lucky to have Sarah Jane."
Elisabeth arrived on CBBC in 2007, and she starred in four series of The Sarah Jane Adventures.