It is his unique double role of being not only an Australian icon, but one with a particular interest in portraiture, that has him returning to Canberra in December for the annual National Portrait Gallery lecture, and the first in the Gallery's new permanent home, now taking shape alongside the High Court of Australia in Parkes.

National Portrait Gallery director Andrew Sayers says Harris's style and his ''unalloyed enthusiasm for people and portraiture'', makes him the perfect fit for the gallery.

In a career that continues to evolve, Harris has found new audiences on British television over recent years for his shows exploring portraiture, and what the National Portrait Gallery is most excited about is Harris will bring his portrait of Her Majesty The Queen that will sit in the gallery on semi-permanent loan.

He says the morning of his first sitting with his royal subject was a terrifying experience in self-doubt.

''We weren't due to meet her until 2.30 in the afternoon, but because of the changing of the guard, we had to be in Buckingham Palace by 11 in the morning,'' he tells me, recalling hours of ''butterflies and panic,'' while waiting, asking himself ''will it work, will I get a likeness?'' How did he find his subject? ''She was very friendly, very charming,'' he says.

With the first sitting taking place on Coronation Day, the pair chatted through the sitting about their very different recollections of the Coronation.

''I told her that I was sitting in Hyde Park,'' he says ''and it was drizzling with rain and I had a blanket around my shoulders, I had the piano accordion, singing Waltzing Matilda to anybody who would stop and listen.''

At their second sitting, the Queen was battling the flu, and so Harris says, rather than paint her at less than her best, he concentrated on her gown and jewellery, which she chastised him for.

''At the end of the sitting,'' he recalls, ''she said to me 'You never painted anything on my face at all, I might just have well have sent my costume on a coat hanger,' and I went hot and cold and took it as a real rebuke.''

It took his BBC crew to point out that she was joking with him, calling it a ''very friendly painting'' as she left the room.

Royal approval for the work alongside incredible public interest (the portrait later drew massive crowds when hung in the Queen's Gallery at Buckingham Palace, and more than seven million watched the television special in Britain alone) has brought Harris a certain respectability and financial freedom.

With his television and performing work leaving him in the fortunate position of being able to paint because he loved it and not because he depended on it for a living, Harris had for years given his paintings away to friends, and never exhibited.

A Rolf Harris artwork now routinely sells in the 40-50,000 ($A80-100,000) range, and recently hitting a record price of 105,000 ($A217,000), ''which scared the hell out of me,'' he confesses.

More important to him than money, however, was a sense of self-confidence.

''There were certain critics who asked what business did I have painting the Queen, but I felt it was good, it did what I wanted it to do, it was a good likeness of the lady and it captured her smile.''

Harris said he was drawing ''as soon as he could hold a pencil'' and credits the encouragement of his father for his success.

''When my dad saw me showing talent,'' he says, ''(he) bent over backwards to encourage me, bought the best paper and paints and watercolour brushes he could afford.''

Himself the son of Welsh portrait artist George Frederick Harris, young Rolf's father Cromwell Harris had been discouraged from the uncertainty of a career in art by his father, but was to take up the brush in his later years.

''Dad always told me I could do anything I want in this life,'' says Harris, ''just as long as you do your homework properly, find out how to do it and get out there and do it.''

Moving halfway across the world to pursue his dream, Harris became disillusioned with art school, and credits another Aussie, his close friend Hayward Veal, a student of Max Meldrum, with teaching him the impressionist technique he continues to work in today.

Stylistically, however, Harris describes himself as a 'realist'.

''I'm an impressionist,'' he says, ''but I paint real things that are recognisable as an end result.

''I paint the blur,'' he laughs, ''and I gradually refine that blur to a state where I am happy with it.''

Rolf Harris will present the lecture Rolf on Art at the National Portrait Gallery on December 3.