JACK Vettriano has a confession to make - and he is certain his former Glasgow bosses will not be pleased.

For two years, the now world-famous Scots painter worked for the Scottish Vocational Education Council in its Douglas Street offices in the heart of the city.

But unknown to his employer, Jack regularly invented excuses to leave his desk and instead headed straight to Kelvingrove Art Gallery.

He admitted: "I used to skive off regularly and go to Kelvingrove. I would arrange a mock meeting and go there instead.

"That was a lovely time when I was just beginning to think maybe I could make a living from painting."

Jack was born in Fife in 1951 and left school at 16 to become a mining engineer.

On his 21st birthday, a girlfriend gave him a set of watercolour paints and from then on, he spent much of his spare time teaching himself to paint.

But during his time in Glasgow, Jack was still questioning whether to give up a paid job and devote his life to painting.And it was partly due to his skives off work that he finally decided to follow his heart.

He said: "Kelvingrove was instrumental in my decision to become an artist because I think its permanent collection is astonishing.

"How lucky is Glasgow to have Christ Of St John Of The Cross by Dali? What a coup that was."

It is fitting then, that in September, Kelvingrove will host the largest exhibition ever held of the artist's works.

More than 100 paintings – some owned by international superstars – will be on public display, many for the first time in 20 years.

Looking back, Jack says he has no regrets about becoming a professional artist.

He explained: "It is the best move I ever made. All I really wanted to do was earn a living and earn enough to pay the mortgage. Little did I know what lay ahead".

In 1989, he submitted two paintings to the Royal Scottish Academy's annual exhibition. Both were accepted and sold the following day.

In 2004, his best known painting, The Singing Butler, pictured left, was sold in Sotheby's for £744,800, a then record-breaking price for a work by a Scottish artist sold at auction.

In total, the auction house sold 14 of his works for almost $3.5million, firmly establishing him as the most sought after Scottish painter in the world.

Jack's work has proved hugely popular with the public and can be seen on posters, mugs and tea towels around the world.

Although international celebrities, such as actor Jack Nicholson and football boss Sir Alex Ferguson have snapped up originals, stuffy art critics have shunned the artist.

Jack admits that is one of the reasons why he was so touched to be asked by Kelvingrove to stage a retrospective of his work.

Gallery bosses approached the artist's agent two years ago and asked if he was planning anything to celebrate his 20th year as a professional artist.

He said: "We were not planning anything and you don't turn Kelvingrove down.

"The people who run that place touch me so much with their kindness, especially when you have had my issues with the art establishment in the past.

"Kelvingrove can put on a Kylie exhibition and an ACDC exhibition followed by the Italian Renaissance painters.

"They really do get it right and you get a feeling you are not dealing with the stuffy, old establishment at that museum, but with a museum that cares for its place and people and services its people very well.

"All these things touch me because I don't come from that side of the tracks. Kylie and I don't have a lot in common, apart from the fact we both breathe."

Jack admitted his agent had been working virtually full-time getting Vettriano owners from Hollywood to China to agree to lend their work to Kelvingrove.

He said: "I have been to the museum several times incognito to discuss everything and there will be a big opening come September, so I will be back then for three or four days."

The owners of all the paintings on loan have been invited to attend but Jack refuses to speculate if any of his superstar buyers will turn up.

Instead he said: "All the buyers will get an invitation and it will be lovely to meet them and find out how they have enjoyed living with them.

"I think I will be really quite touched when I see all my paintings – I wouldn't want any cameras around in case I shed a few tears."

l The Jack Vettriano exhibition opens in Kelvingrove Art Gallery And Museum on September 21 and runs until February 23.