National treasure Sir David Attenborough has made his debut on Twitter - and received a message from space.
The veteran wildlife broadcaster was involved in a live question and answer session ahead of the finale of his BBC1 show Africa, responding to viewers and fans.
Among the messages was one from Canadian astronaut Chris Hadfield who contacted the 86-year-old from the International Space Station.
Commander Hadfield - who is seven weeks into a five-month mission - asked: "If you had an evening to spend here on the Space Station, how would you spend it?"
Sir David, who took part in an hour-long session, told him: "I'd just sit and watch the Earth go by - it's a perspective I've never had."
At one stage his Twitter session was proving to be more talked-about on the networking site than a simultaneous chat which was being hosted by football star David Beckham.