The prince, who visited the programme's set in Manchester on Friday morning, was not the only celebrity making a cameo appearance - 70s rocker Noddy Holder and Sir Trevor McDonald also made a visit to the Street.
The special hour-long drama featured a pre-recorded clip of him in a television news bulletin meeting Councillor Audrey Roberts, played by Sue Nicholls.
The prince, who visited the programme's set in Manchester on Friday morning, was not the only celebrity making a cameo appearance - 70s rocker Noddy Holder and Sir Trevor McDonald also made a visit to the Street.
After 40 hours of rehearsals, the 36-strong cast showed little sign of nerves and there were only two or three hiccups during the first episode not to be pre-recorded since 1961.
Minutes after viewers watched Weatherfield residents crack open the champagne after a victory for the Save Our Street campaign - to save the famous cobbles from being tarmacked - the cast were able to celebrate for real.
Earlier in the day, the Prince had laughed and joked with actors and production staff as they prepared for the live broadcast.
He told Ms Dawn: "All of the viewers would be horrified if you don't wake up."
The Prince was also there to unveil a plaque to commemorate the ITV show's anniversary.
The plaque was unveiled on a wall next to the famous Rovers Return pub, but it will eventually be moved to a green room where cast members relax between scenes.
He took time out to enjoy a scotch at the bar of the Rovers Return pub, where he joked with actress Denise Welch, who plays landlady Natalie Barnes.
Eighteen years ago the Queen paid a similar visit to the Street, which broadcast its first episode on 9 December 1960.
Prince Charles praised the show as "a wonderful institution in this country".
He promised he would be watching the episode.
"Having met everybody I understand why everyone gets so involved in Coronation Street," he said.
There have been more than 3,500 characters in the soap since it began, as well as 25 births, 82 deaths and 51 weddings.
The soap began life as a live series but this was replaced in favour of recordings a year later.
Prince Charles also met the show's creator, Tony Warren, and signed a copy of the script for the live episode, which is being auctioned next week to raise money for the Manchester Christie cancer hospital.
Mr Warren said he had also received a letter of congratulations on Friday from Prime Minister Tony Blair.
Granada Television spokeswoman Alison Sinclair said the cast, who normally film scenes without rehearsal, had welcomed the challenge of the live episode.
She said: "Everyone has a real sense of being involved in television history."
The cast of its BBC rival, EastEnders, sent a bouquet to the cast of the Street, wishing them luck for the live transmission.
But one character, Fred Elliot, was absent from the special, as writers had to make last-minute changes to the script following the stabbing of actor John Savident last week.