In the current climate of celebrity confession, it is hardly up there with illegitimacy, addiction and petty crime, but before Charlotte and Kelly made it trendy (and despite Shirley and Tom), Petula Clark did not exactly draw attention to being Welsh. That would have been contrary to her cosmopolitan image.

In the days before the "c"-word meant a cocktail for singletons on the lash, Pet Clark was a trans-boundary international star, whose ability to croon as effectively in French as English had made her a star on both sides of the Channel with a French husband and a home in Switzerland. She sat above our local lasses - Sandi, Cilla, and even Dusty - as being just that bit more sophisticated.

This year, however, Petula Clark made a BBC programme called Coming Home that took her back to her roots in the valleys. After half a century in showbusiness (she was a child star in the movies of course), she has nothing to prove to anyone any more.

"I had no musical education," she remembers, "and I suppose we were lower middle class, but during the war at some point we had a piano and I taught myself to play it by ear."

Although she emphasises her lack of formal expertise, it is clear the Clark is far from uninterested in the technicalities of her craft. She has worked with the same musical director, Kenny Clayton, since her French career in the 1960s, barring a spell when union regulations would not allow him to work in the States.

"Harmonies are very important to me," she says. "I would like to have been an arranger." I wonder if, like an opera singer, she has been conscious of changes in her voice during her career.

"I still sing the hit songs in the same key," she states with some pride, but she acknowledges learning different techniques along the way.

"Sunset Boulevard was a hard show to sing, and I played that for two years, one on the West End and one on tour in the States. When I perform With One Look during my concerts now, I am conscious of using that voice. The pop stuff requires different technique. My voice is much stronger now than it was when I had my hits; I have much more power."

"As well as other show tunes, from Blood Brothers and Finian's Rainbow, those hit songs form the basis of the show she is bringing to Aberdeen, Perth and Glasgow next week. She runs through them in bandstand shorthand - Downtown, Subway, Other Man's Grass - and there are a lot of them.

"It's a very personal show," she says. "I don't do covers of other people's songs."

The words "because I don't need to" hang, unspoken, in the air.

Clark's class comes from being a singer's singer. She recently performed for the first time in years in Paris, a date at the Olympia for which she confesses to having a rare attack of nerves.

The French, eager to put their own stamp of chanson tradition on the 1960s beat boom, bracketed her with their own Ye-Ye girls, a piece of mini-skirted kitsch that has recently enjoyed a revival of interest.

Clark, however, is suspicious of putting too much fashionable stress on a very brief period in her long career. "Yes, I was a sixties person, but I moved away from that and I have done a lot of things since." For many years, the mainstay of her work was variety television, one of those sainted personalities whose name alone was enough to sell a series that attracted the top flight of guest artists.

Twenty years after they disappeared from our screens, she is not one to have their comparative innocence disparaged.

"They were great shows we all had back then. They were beautifully produced and, importantly, they allowed us to sing other stuff than the chart hits that had made our name. I regret their passing."

Clark's development from pop starlet to international artiste on those shows has been documented recently on an album that gathers together duets that she has performed, sometimes on record, but more often for the television cameras.

SASHA Distel, Matt Monro, pianist Oscar Peterson, Bobby Darin and Andy Williams are among her singing partners on the disc, and she was singing live recently with the veteran Williams, who is still finding those high tenor notes at his great vintage.

Whatever they learned from the production schedules of those weekly TV series, it has lasted well. Of her more recent collaborators, Clark's favourite shows her continued good taste, as the first name she cites is that of former Doobie Brother Michael McDonald, another musician's musician often cited as the favourite voice of folk with discerning ears.

"We have worked together and we get on very well. I am not really a party animal, but we do seem to have ended up singing together at parties."

Of her own celebrity endorsements, the one that gives Clark the most pride is the report that she was John Lennon's favourite female singer.

However, that is not the reason why, if you listen closely, you'll hear her on the Plastic Ono Band's Give Peace A Chance. Her story of how she wound up in the Montreal hotel room where John and Yoko were staging their "bed-in" for peace both illustrates the guru status of the former Beatle at the time and casts her as the supplicant, struggling with the politics of her multi-lingual career.

"I'd been staying in French-speaking Canada but was starting to have hits with records in English as well. So when I was booked to perform at the Place des Arts in Montreal, I thought I'd do a bi-lingual show. Wrong."

Clark, plainly naive about the tensions in Quebec, found that her skills only fueled the division in the crowd, with the French speakers shouting down the English songs and the Anglophones yelling back. "It was open war," she says.

"After the show, I was upset and I went to John's hotel to ask his advice. I didn't really know him that well, but I do remember he was very rude about the audience.

"There was a very strange atmosphere in the suite and I remember the cameras being there but I really didn't realise they were making Give Peace A Chance at the time."

Home for Clark is still Geneva and there is a chalet in the French Alps. For London stopovers she has "a tiny apartment in Chelsea" and in the US "a place in Miami I never see". Daughters in New York City and Paris provide further accommodation options but it is her son, who lives in Geneva, who might decide to join her in Scotland next week. For the golf, of course.

"I am truly looking forward to being in Scotland," she assures me. "It is a blessed place." Of course, as befits an international star, for Scotland she means Gleneagles.

Petula Clark plays Perth Concert Hall, Sunday, Aberdeen Music Hall, Monday, and Glasgow Royal Concert Hall, Tuesday.