Dame Diana Rigg has confessed she struggled to keep a straight face acting with her daughter in Doctor Who.
The actress, 74, - who made her name in roles such as leather-clad, karate-chopping Emma Peel in The Avengers and in the 1969 James Bond film On Her Majesty's Secret Service - appears in the sci fi drama this week with her daughter Rachel Stirling.
Dame Diana said: "Rachie and I had great difficulty keeping a straight face in some scenes.
"Hopefully we're believable. I play a horrendous old bag who wants to take over the world. I love playing old bats....
She continued:"I don't think there's any competition between us. Each generation has to re-interpret the great parts for themselves, which is why the theatre remains fresh."
Dame Diana also revealed that she had never turned her back on The Avengers.
"It's true I'm not big on reunions, and fans get miffed when I don't turn up, but it made me well known worldwide.
"I'd have had to spend 150 years touring to get such an audience. Fully grown, not to say 'mature', gentlemen, come up and say, 'I saw you when I was a boy'", she said.