David Tennant will undergo surgery for a prolapsed disc and will not return to his Hamlet role before Christmas, the Royal Shakespeare Company has said.
The Doctor Who actor was said to be "gutted" after he was forced to pull out of the show on Monday night due to an ongoing back problem.
He also missed the press night at London's Novello Theatre, but his understudy, a relative unknown called Edward Bennett, stepped in to face the critics - and won standing ovations in the dream role.
Bennett, who normally plays Laertes, will continue to perform as Hamlet, the RSC said.
He was praised by Tennant, who said today: "It is hugely disappointing for me to have to miss these performances. My back problem has progressed to the point where it is currently impossible for me to carry on without surgery.
"I want to get back on stage as quickly as possible and I am very grateful to Ed who has courageously got to grips with the role but in a much shorter time. It's a fantastic achievement."
As is usual policy, the RSC and Delfont Mackintosh Theatres will not be issuing refunds because the Company has a fully rehearsed understudy policy and performances will continue as scheduled.
The Company will offer exchanges, subject to availability, for other RSC London performances during the season at the Novello Theatre. Patrons are also able to offer tickets for resale, however resales are not guaranteed.
Artistic director Michael Boyd said: "We all wish David a speedy recovery and it is an indication of the RSC's investment in understudies that Ed Bennett can take over Shakespeare's largest role at such short notice.
"As an ensemble company, we feel it is important to go ahead with the run at the Novello Theatre and I am proud of the way Ed, the understudies, Patrick Stewart, Penny Downie and the rest of the company have risen to this challenge, getting a great reaction from audiences and critics alike."