Karen Gillan is to leave Doctor Who during the next series.
The actress - who plays Amy Pond - will be written out in a "heartbreaking" storyline, show boss Steven Moffatt said.
A new companion for The Doctor is being lined up but producers said they would give no clues about their identity.
Karen and her screen husband Arthur Darvill - who plays Rory - will both be written out.
The Scottish actress, who will soon be seen in a BBC drama as Sixties model Jean Shrimpton, has had a starring role for two series and has become hugely popular.
Matt Smith said he would miss his co-star, who joined the programme at the same time as him.
He said: "We took over the show and we really had to hold hands and help each other through it. It's very disappointing. But this show is about change and regeneration."
Photo: © Rex