Wimbledon is gearing up to celebrate 100 years of its iconic Centre Court, described as a "white elephant" when it opened, as it launches a new tradition of playing on the middle Sunday of the tournament.
The event will look back on epic matches and classic moments, with past Wimbledon champions involved.
"It was described as this white elephant," Willis said on Friday. "How on earth would the club ever fill it?
"How would tennis ever be so popular so that you would welcome so many people? "And obviously here we are 100 years later and this wonderful stadium is 100 years old. It's become one of the most iconic landmarks is all of sport."
The grass court stadium, with a capacity of nearly 15,000, is a mixture of the traditional and the cutting-edge, including a retractable roof that allows play to continue in the rain. The Wimbledon site is set for expansion over the coming years after the All England Club's purchase of the adjacent Wimbledon Park Golf Club, where a new show court will be located.
Willis said the focus of Sunday's celebrations was both on looking back and looking ahead, with school children asked to imagine what Centre Court would look like in 100 years' time.
"This idea of it being a witness to history," she said. "If you think about how much change has occurred.
More than 14,000 people have been invited to Wimbledon from the local community on Sunday and there will be around 1,000 refugees from Ukraine and 500 from Afghanistan and Syria.