This year's programme features an eclectic mix of performances and appearances including Belfast's own Van Morrison, Irish President Michael D Higgins and comedian Dara O'Briain to name a few.

But when the festival began 50 years ago, it was a much smaller affair.

Betty Craig, assistant director between 1973 and 1986, was celebrating the landmark achievement on Thursday.

"It started from such humble beginnings and within about five years we were the second biggest largest festival in the UK," she said.

"In the beginnings we used to think of ourselves as a festival family and the staff were always wonderful, and that's the basis for a good festival."

I think it's incredibly important as it helps bring culture to the masses, and there should be something in the festival programme for everyone no matter what their age and no matter what their interests.

Betty Craig

She said it was much more difficult to attract artists to the city during its early days.

"In the 70s it wasn't easy to get artists to even talk to us, and when I used to phone agents and I know that my enquiry never actually reached the artists themselves, so I'd actually heard Ralph McTell.. (he) said he'd loved to be on stage with Billy Connolly.

"And I was listening to this at home and I thought, I'm going to get them together. We put them on for six nights and it was a tremendous success, it was wonderful to have Billy."

Rowan Atkinson became a friend of the festival after Betty scouted him out at Edinburgh Festival, when she was one of few in the audience to see the then unknown comic.

Robert Agnew, executive director of the festival from 1994-2000 began working for the event from 1980.

He said it was difficult to organise and fund a new event every year but said when things went well it had a 'joyous ambiance'.

"Suddenly in November, you opened the door and all these artists flooded in from all over the world, we had international orchestras, we'd theatre companies from Lithuania, Romania, it was just a magic, magic time," he said.

"There is particular warmth in Belfast for artists performing and giving their utmost," he said.

He notes particularly, the principal director of the Leipzig Gewandhaus Orchestra during a visit describing "the friendliest festival in the world".

To mark its 50th anniversary, the festival is running a project with the Heritage lottery fund- the Belfast Festival Anthology.

The anthology will let the public share their memories and pictures of the festival online. An exhibit at Belfast City Hall and at Queen's University will chart the growth of the festival from small student bash to multi-million pound event.

And look out for red plaques which will mark the places and venues that have had key importance to the festival and the culture of Belfast.