07/05/2016 19:45 BST | Updated 08/05/2017 06:12 BST

Happy 90th Birthday David Attenborough!

If you didn't already know it, today is Sir David Attenborough's 90th birthday. Rightly, there will be thousands, possibly millions of people sending him best wishes for the day. On the phone to his daughter Susan on Thursday she told me she could see the postman staggering up the path with three huge crates of post and I suspect it's been the same all week.

I had delivered my own card some days earlier, together with a DVD of a TV programme called Attenborough at 90 the end result of a project that had begun a year ago. Last summer I had been given the job to add to the Attenborough Birthday celebrations by producing a special programme to celebrate both the happy day and his life's work for the BBC.

Clearly, a lovely thing to do, and right from the start I was not in the slightest concerned about filling an hour with wonderful stories, clips and anecdotes courtesy arguably the worlds foremost storyteller. However, there was one slight problem - persuading David to agree to actually take part.

His first reaction ranged from: "Oh no its too much fuss" to "Will anybody really be interested?" I should say that this is not false modesty, in fact is rather typical of David, he's always been more interested in the content of his programmes than in his personal involvement and genuinely feels the audience should be too. Undaunted, I persisted, and after repeated attempts over a number of months, and with the promise that Kirsty Young would interview him and that there would be no choir of tiny tots singing happy birthday, he finally agreed.

As part of the negotiations we also agreed that, whilst of course it would revel in his past adventures, the programme should be forward looking as much as possible, connecting his past work with the latest breakthroughs in filming technology, the discovery of new and amazing animal behavior and with new approaches to conservation.

With that understood plotting the programme could begin and, while I was right about there being no shortage of stories to tell, it was soon clear that there was almost too much to choose from, after all this needed to reflect more than 60 years of work.

An early coup was filming an interview with Charles Lagus, David's companion and cameraman on the Zoo Quest series. Charles, a youngster at only 88, vividly recalls the wonderful innocence and freedom of those first days of Natural History filming back in the 50s, and the emergence of the Attenborough presentation style.

Perhaps David's most powerful signature is his 'pieces to camera', the moments in his films when he is interacting with an animal or some other aspect of nature. As one of the lucky people who have had the enormous fun directing some of these 'pieces' around the world, I relished the chance to pick some favourites for the programme. As well as the classic frolicking with the mountain gorillas (from Life on Earth) there are meetings with giant dinosaurs, with bioluminescent earthworms, blue whales and even a baby rhino.

Alongside these magical moments it was impossible not to touch on some of the more hair-raising moments in David's career. There is a kind of unofficial club of directors that have taken their enthusiasm to get David just that little bit closer to a big wild animal or into some other white-knuckle situation, to a point that most people would blanche. There is Alastair Fothergill's notorious 'bubble helmet' (mentioned with a shudder by David in our programme) the various high-wire stunts devised by the late Adrian Warren, and even my own contribution; getting David to crawl under a giant termite mound full of nasty, biting, stinging soldier termites. In our defense I should mention there was no shortage of encouragement from the man himself - David's is only too eager to do our bidding if it helps reveal something extraordinary about the natural world. (I've only ever heard him demur once and that was to a crazy idea involving male chimpanzees the details of which are best left unsaid).

Somehow over all the years of these adventures everyone has come back in one piece - just as well, as Alastair has said no-one wants 'responsible for bumping off David Attenborough' on their CV!

As part of the birthday celebrations we managed another first (and a little surprise for David) by linking up with the Oscar winning Aardman Animations to create a trio of short films, (in the style of Creature Comforts), that gives the animals perspective on some of David's most memorable animal meetings. They're called 'The day I met Attenborough' and the animal stars are that famous gorilla family, two star-struck penguins and an enthusiastic Attenborough impersonator, in the shape of an Australian lyre bird.

One of the hallmarks of David's programmes has been his unbounded enthusiasm and energy and its clear from his birthday programme that, even at 90, this does not seem show any sign of fading. He talks with relish about how last year he dived beneath the waves in a mini-submarine to explore the Great Barrier Reef and how he joined an excavation in the remote deserts of Patagonia on the trail of the worlds largest dinosaur (his joy at being hands-on with such an extraordinary fossilized creature was palpable). And his adventures are still going on - a few weeks ago I flew with him in a hot air balloon at 11,000 feet over the Alps to film the opening of our new series Planet Earth II.

When asked why he keeps so busy David says he simply loves making programmes - telling new exciting stories and working with pals. I think I can safely say that the feeling is mutual - people often say to those of us that make wildlife films that it must be a great job - yes it is, but nothing compared to making wildlife films with David Attenborough - that's the truly great job.

Long may it continue - Happy Birthday David!

Attenborough at 90 is on BBC1 Sunday 8th May At 7.00pm.