Ex-pupils and rugby internationals Tom and Ben Youngs were the special guests at Gresham's in Holt as it marked the end of the academic year.
Former professional cricketer Matthew Fleming also attended, and a new on-site outdoor activity centre was also officially opened.
Tom Youngs said: 'I have fond memories of my time here and I remember so many opportunities to excel. The sports field really helped me to find my feet, develop my passion, and build my work ethic – and not only on the rugby pitch. Hard work gave me the reality of living my dream and my advice is love what you do, and do what you love.'
Ben Youngs also spoke and congratulated prize winners.
He said: 'My words of advice for the future are be bold and have a go, whatever the outcome may be. I was afraid as a pupil to fail in the classroom, but I've learnt that through failures come the best of life's lessons, so a fear of failure is no reason not to have a go. I feel really lucky to have attended Gresham's. I've been dropped from teams and lost in world cups – but failure definitely made me a better person.'
Guest speaker Matthew Fleming, who went to Eton school, said: 'Don't be afraid to fail.'
The new outdoor activity centre features a 21 obstacle armed forces standard assault course, a 250 metre zip wire, high and low ropes courses, abseiling facilities, and a 20 person purposefully basic bunkhouse.
The centrepiece is the 28-metre Bourdillon Tower named in honour of Tom Bourdillon, Gresham's alumnus, and half of the two-man team that came within 300ft of Everest's summit, just three days before Edmund Hillary and Tenzing Norgay reached the top in 1953.
The school welcomed his widow, Jennifer Bourdillon, to officially open the new facilities.
Gresham's headmaster Douglas Robb said: 'What a fantastic new facility. We hope Tom's legacy, love for adventure, and determination to overcome failure – alongside the sage words of advice from our speech day guests Tom, Ben and Matthew – will inspire pupils to forget about failure and just have a go for decades to come.'
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