Frank Bruno received a standing ovation when he made a surprise appearance at the 75th Royal Variety Performance.
Rachel Stevens, Frank Bruno and Cat Deeley greet the Queen
The former world heavyweight boxing champion was making his first public appearance since his high-profile battle with depression.
He was flanked by singer Rachel Stevens and presenter Cat Deeley as he greeted the Queen at the start of the evening.
Bruno was introduced on stage by comedian Ronnie Corbett at Edinburgh's Festival Theatre.
Security was tight at the event, although police dismissed newspaper reports of a specific terrorist threat.
Two newspapers said that al-Qaeda may have been planning an incident to coincide with the performance.
But Lothian and Borders deputy chief constable Tom Wood said there was no specific threat to anywhere in Edinburgh or the rest of Scotland.
"The Royal Variety Performance is a high-profile event and with the presence of Her Majesty and Prince Philip, it has been given the usual high level of security attention," he said.
"The current state of alert across Britain is at the second highest level.
"That means that there is intelligence of a threat to the UK but there is no specific information about a target or a time and place.
The Queen enjoyed a range of acts
"Everyone should be alert but there is no need to panic."
The Queen and the Duke of Edinburgh were greeted by Lord Provost Lesley Hinds on the red carpet.
It was the first time that the Royal Variety Performance had been staged in Edinburgh.
Opera star Luciano Pavarotti headed the cast, which also featured the pop band Busted and the American singer Donny Osmond, who was joined on stage by his five brothers for a rare public performance.
Money raised by the 75th Royal Variety Performance will go to the Entertainment Artistes' Benevolent Fund.