TV naturalist Sir David Attenborough has been invested with one of Britain's most coveted honours - the Order of Merit - at Buckingham Palace.
The Order of Merit is restricted to only 24 British members
Sir David said he thought he had been chosen because he had reached "so many people through television".
Former Commons Speaker Baroness Betty Boothroyd also received the order.
This special award from the Queen is for people who have shown exceptional merit in learning, the arts, science, literature or the public services.
It is restricted to 24 British members and entitles those who have been awarded it to use the letters OM after their names.
The broadcasting career of Sir David, 78, has spanned more than 50 years, with acclaimed series including The Living Planet, The Trials of Life and The Life of Mammals.
The 13-part series Life on Earth, written and presented by Sir David in 1978, was alone watched by an estimated 500 million people worldwide.
In 1965 he was appointed controller of BBC2 and was responsible for the introduction of colour television into Britain. From 1969 to 1973 he was the BBC's director of programmes.
Speaking after receiving the award during a private audience with the Queen, Sir David said: "How could anyone believe they actually deserved something like this?"
Lady Boothroyd, who was the first woman Speaker of the Commons, said earlier that she was "greatly honoured" at the award.
"I would like to think [the honour] is in recognition of my services to Parliament over many years and, of course, my Speakership of the House of Commons."
Andrea Levy, author of the novel Small Island, was presented with the 2005 Commonwealth Writers' Prize.