Bennett the Hamlet understudy 'thought the audience would walk out'

When Elizabeth Bennett had a call from her son to say he was taking over from David Tennant as Hamlet she burst into tears. With just three hours' notice, the 29-year-old understudy had to prepare himself to walk out on stage in front of a theatre full of Doctor Who fans unaware the TV star was stricken by a bad back. But for Edward Bennett there were few prizes as precious as the Prince of Denmark.

"He called to say he was playing Hamlet," said Mrs Bennett, 55. "It was unbelievable. His hands were shaking so much it took 10 minutes to tie his shoelaces.

"He looks calm but underneath he was scared. His one aim was to play a serious role in Shakespeare. That was his dream."

For Mrs Bennett, who lives near Stratford, the next few hours were agony as her son – just four years out of the Royal Academy of Dramatic Art (Rada) – stepped up to a role considered the most challenging in theatre. "I kept looking at the clock thinking he will be on stage now, it will be half-time, he will be finished," she said.

"I rang that night. I couldn't wait until the morning. He said that during the first half he was really quite nervous but during the second half he enjoyed it and relaxed.

"He was worried the audience were going to walk out – all those 16-year-olds who were in love with David – but they didn't. He just stood with tears rolling down his face at the end because of the standing ovation. He is usually very understated emotionally."

Just hours before curtain-up, Tennant, 37, was forced to pull out because of a slipped disc, announcing that his enforced absence was "hugely disappointing". But Bennett was prepared, despite slipping off to Egypt for a holiday with his girlfriend, Natalie Walter, during a break between performances in Stratford-upon-Avon and the Novello Theatre, London.

"They had a 10-day break but he kept going through his lines and it is a good job he did," Mrs Bennett said. "Natalie is an actress as well [with the RSC in A Midsummer Night's Dream] so she is very supportive." She said that although Walter was Tennant's ex-girlfriend the two men were good friends. "Edward looks up to David. We are all very sorry for him – he had done a superb job."

Mrs Bennett, a former secretary, has seen this production five times, but will still be nervous when she goes to see her son in the West End next week. This is not the first time Bennett has been forced to step up and take on Hamlet. While reading politics and history at Cardiff University, he organised a performance of the tragedy as director but ended up taking on the role himself when the lead pulled out.

Bennett announced his ambition to act after seeing Chekhov's The Seagull at the RSC's Swan Theatre in Stratford aged 14. On his big break, Mrs Bennett said: "You always hope it is going to happen for your child. I am quite reserved but we feel like shouting it from the rooftops."