Veteran nature show presenter David Attenborough underwent emergency heart surgery in London on Tuesday to insert a pacemaker, forcing him to cancel a sell-out tour of Australia next week.
Attenborough, 87, known for his wildlife documentaries, was due to visit Canberra, Perth, Adelaide, Sydney and Melbourne on his "A Life On Earth Tour", speaking to audiences about his career and the evolution of filming techniques.
A spokesman for Lateral Events, promoter of the tour, said doctors were satisfied with Attenborough's progress following the operation, adding the broadcaster was his "lively self".
The BBC presenter, whose programs have included "Life on Earth", "The Living Planet" and "Frozen Planet", most recently narrated and presented the TV series "Africa".
Attenborough, who was knighted in 1985, expressed his "extreme disappointment" in a statement at having to cancel his tour of Australia, adding that he hoped to reschedule in the near future.