Kumbuka, the lowland silverback gorilla, has been found after he escaped from his enclosure at London Zoo.
Armed police had been called to the central London attraction and visitors were evacuated as keepers desperately tried to recapture the loose animal.
Despite the escape a spokesman for the zoo said visitors were "never in any danger".
Malcolm Fitzpatrick, curator of mammals at the zoo, described the escape of Kumbuka as a "minor incident" in which the male gorilla got into a secure keeper area that was not open to the public.
Fitzpatrick said the western lowland had been tranquillised before being returned to the Gorilla Kingdom, where he was "up and grumbling and interacting with the rest of his gorilla family".
Earlier reports had painted a different picture. Neuropsychologist Dr Jonathan Mall was at the Weird and Wonderful World of Field market research conference when the incident happened at the zoo.
Mall, 33, said he had gone for a walk during a break in the programme and was next to the gorilla enclosure when a siren went off at around 5.20pm, and a call over the speakers asked for staff to urgently go to the site. He said he saw two members of staff "frantically running around" in the enclosure, and when he jokingly asked one if a gorilla was loose they said: "I don't know, please go outside the area."
"Another distressed staff member said 'Please move quickly and go inside a building', and she told us to leave, I saw other people running for buildings," said Mall.
Mall and other visitors were forced to hide inside a bird attraction, stranded for around half an hour while staff tried to bring the loose gorilla under control. He said another speaker at the conference had seen one of the gorillas acting "really agitated" in its enclosure around 15 minutes before the escape, saying it had repeatedly run towards the glass walls and hit it as people took pictures of it.
London Zoo say the incident is under investigation.