Sir Alan Sugar, along with nearly 50 figures from sport, television and politics, has taken time out from firing would-be apprentices to say good luck to GCSE pupils as they sit their exams.
Since Easter, Mike Sandeman, head of Arthur Mellows Village College in Peterborough, and Sarah Schaffer, his PA, have contacted more than 300 celebrities they consider to be role models, requesting signed photographs with encouraging notes for Year 11 pupils sitting their GCSEs.
Mr Sandeman said: "All schools are looking for that added extra something. Like all good ideas, I borrowed it from someone else and developed it with my PA."
They were overwhelmed with the response and have received letters from successful role models with different backgrounds, including all three party leaders, former prime minister Tony Blair and actress Keira Knightley.
"Our big worry was whether anybody would reply. We did not want to send all the letters out, get nothing back and feel stupid," Mr Sandeman said.
"I thought we might get a few C or D-list celebs, but these are people I, as a headteacher, can look up to - and my pupils can, too."
Originally, 150 letters were sent, but after talking to pupils it became clear there were other figures who had experienced success in specific fields who might be a source of inspiration to individuals or groups in the year.
"As adults, we must be careful not to imprint our own views on pupils," said Mr Sandeman.
"I might think Sir Steve Redgrave is an amazing role model, but despite his track record Russell Brand's message has also had a profound effect on certain pupils," said Mr Sandeman, who added: "The female staff, on the other hand, were far more impressed with (actor) Colin Firth's message.
"Different groups at school are aware of different people and I am not here to judge but to provide a cross section.
"It would have been a mistake not to put Russell Brand's message up there if it makes a difference to someone as they sit their exam."
The school is still receiving replies, the last being from veteran TV entertainer Bruce Forsyth. Many are hoping that responses, especially from certain VIPs in America, will continue to filter through over the summer.
Mr Sandeman said: "The pupils were surprised and it has had the desired effect. By replying, it feels that these people and their achievements are closer to the pupils."
The replies are being posted on the Wall of Inspiration in the foyer outside the exam hall. Cryptic clues in the pupils' form-time bulletins encourage them to guess which new celebrities they might see up there before their next exam.
After their English exam this week, some pupils spoke to The TES about how the wall has affected them.
Oliver Aird, 16, said: "At first I thought not many people would take the time, but they did. The messages from people such as Gordon Brown have really helped.
"I was pleased to see Gordon Ramsay's message because I have read his cookbooks and autobiography. He has worked his way up and is well known. It makes us realise we can follow in his footsteps."
Rebecca Brocklesbury, 16, said: "Schools need to look at different aspects of what pupils are interested in. All the people up there have their own story and show there is a different world out there.
"I was most impressed by Keira Knightley because she has made such a name for herself and has achieved her goals."
The school received some letters from celebrity agents who said their clients could not reply to requests like this because they were too busy.
Mr Sandeman said: "It seems strange that Dame Kelly Holmes does (reply) and (Sir) Alan Sugar can send a lovely letter for the pupils.
"I wonder if these celebrities even know their agents are giving out negative responses."
The school plans to build upon the Wall of Inspiration year by year, adding new messages as it receives them.