Norman Foster is used to media attention and, in the 40-year history of Foster + Partners, has become adept at avoiding it.
But not on Wednesday last week. An excited call from the 71 year old's PR to the AJ's news desk ended with these words: 'Get down here by four; the deal is being signed at quarter past?' 'Here' is Foster + Partners' riverside HQ in Battersea, south London, and the 'deal' was private-equity investor 3i's decision to buy a minority stake in the firm, valuing it at £300 million.
So to 22 Hester Road where, after passing a row of around 40 stylish and mostly young architects squeezed into a long, narrow café bar, the familiar tanned face of Lord Foster of Thames Bank materialises and we are steered into the inner sanctum of Foster + Partners.
Foster's love of skiing, running and a healthy lifestyle have kept the ravages of age at bay, but by just how much is surprising. With his 72nd birthday looming, Foster could easily be mistaken for a man in his 50s.
At a sprightly pace we walk past champagne-laden trestles through a huge and busy open-plan office to a table at which are seated Fosters stalwart Mouzhan Majidi and 3i head of UK capital growth, Steve Nichols - two men at the heart of the radical changes that Foster is about to announce.
As well as marking the 40th anniversary of the firm (on 9 May), the meeting has been timed to coincide with two other events: the broadening of the firm's ownership and the signing of the much-talked-about 3i cashinjection deal.
Taking advantage of an expectant hush, Foster begins: 'Before today we were four shareholders and now we are 14. Simultaneously we have broadened the financial base of the company and created a platform for the future with 3i coming in as minority investor.'
Those structural changes are a progression from the firm's 2005 shake-up, which saw the creation of six new 'Design Groups'. Even then, on the back of his success leading the design of Stansted Airport and his role on Hong Kong Airport, Majidi was a clear contender to take over the running of the Foster empire.
Foster says: 'Mouzhan has moved into that position and that for me is absolutely fantastic. He will take over quite a lot of the day-to-day running of the company and I will be able to concentrate on a lot more design.
'I will also look strategically at the bigger picture, ' he adds.
That 'strategic picture' covers a large canvas including 22 offices across the globe which, according to the softly spoken Majidi, control around 200 projects at any one time.
In addition to tackling the opportunities available in mass markets such as India, China and the Middle East, Foster says the 3i money would enable the company to consider other ventures.
'We are aware we could significantly increase our skills by acquisition, the bringing in of specialist engineering skills, and maybe we could control better the execution of our projects by developing project management; that would be fantastic and attractive to our clients, ' he says.
Although Foster says he is 'not going to leap into anything, ' by his own admission he is relishing the next stage of Foster + Partners' development.
'I'm really excited by the fact it liberates me to do more of what I want to do, ' he says.
'I will travel more and I like the idea of travelling to some of the places where we have a fipotfl we haven't tapped.
It is not a step back for me - it's a step forwards.'
Talk of the future causes Foster to pause as he takes stock of his momentous rise from the early days - including his Team 4 partnership with Richard Rogers - to the practice today which employs 1,000 staff around the world.
Foster says: 'At the beginning of those 40 years I really did everything, from making the tea to opening doors. There are one or two buildings from that time where I can tell you the dimension of every steel member and the tolerances on the window system. I could write a bible on those projects.'
Foster's iconic buildings are all testaments to his skill, but what he is perhaps most proud of is the dissemination of these skills to a new generation.
He says: 'Over that time what inevitably has happened is that I have sought to use [my] skills to be able to work with others and to encourage others to share the excitement and the quality of those buildings in a broader team.'
Making reference to his days as a student at Yale University, Foster pays tribute to the teaching skills of architectural legends Paul Rudolph, Serge Chermayeff and 'Bucky' Fuller.
But it is to the next generation of architects that Foster is really looking and, as if to prove it, he leafs through the brochure of the company's forthcoming graduate show, oblivious to questions as he proudly reels off project after project that his new generation of architectural starlets have submitted.
And who knows, one of those starlets may even be a Foster: 'I'm looking forward to my children joining the firm, ' jokes Foster, before rushing off to join those already tucking into the celebratory champagne.