DIANA ROSS is spending her 25th year in show business on a world tour. ``So far, we've been to 26 countries,'' she notes in an interview. ``When we wrap the concerts in the US, then it's Australia and Japan. The tour winds down the end of this year.'' Ms. Ross sang to an SRO crowd in London's Wembley Stadium, and HBO taped the event. The result - ``HBO World Stage: Diana Ross Working Overtime'' - premi`eres Saturday (10-11 p.m.) and plays throughout the month on the cable network.
Her tour has been sold out in every stadium and amphitheater, and Ross is loving it.
``I was away for 18 months to have two babies,'' she says with a smile, ``and suddenly there I was - planning this tour, designing my own gowns, selecting songs, and nervously hoping audiences would find me singing better, looking better, entertaining better than ever.''
Her worries were groundless. After 55 albums, an Oscar nomination for ``Lady Sings the Blues,'' and countless Platinum hits, Ross still works with the drive and energy of an Olympian. Her two new records, ``Working Overtime'' and ``Paradise'' make clear that her star quality hasn't diminished.
What has changed is her private life. Almost four years ago, she and her three daughters were vacationing in Bermuda, when the children met two girls their ages and a boy. They turned out to be the children of Norwegian shipping tycoon Arne Naess. On that vacation, Ross and Naess became friends. Five months later, they were married in a civil ceremony in New York.
Ross really had wanted a big wedding with all her friends attending. So the following February, they were remarried in Switzerland. It was a fantasy ceremony: The Norwegian Silver Boys Choir sang; the happy couple cut a chocolate wedding cake; and Stevie Wonder entertained at the reception.
``Life with Arne is so different,'' Ross says. ``He's a mountain climber, a skier, sailor. He can do any sport like a professional. Since meeting him, I've had adventures people do not know about. I never thought this little Detroit girl would ever go to Nepal, climb the Himalayas, or be in the bush country in Africa. In show business, you can get all wrapped up in glitz and glamour. Arne balances my life. These outdoor adventures, which he's constantly introducing to me, make me feel connected with real things.''
TODAY Ross looks back on the first 25 years of her career, and says, ``Life has never been horizontal for me. There are always big leaps, up and down. Whatever happened, always the music was there.
``When we were just kids,'' she continues, speaking of Mary Wilson, Florence Ballard and herself, ``we were turned down by Motown, but we just hung around, watched, and made pests of ourselves until they let us record.
``A big turning point was when they named us the Supremes. We had seven No. 1 singles in a row. Going solo was another big step for me. Leaving Motown was another. And now, today, going back to Motown as a part owner of the company is a quantum leap.''
There are some things that haven't changed about Ross, though. She is still slim as a clarinet, determined as a Marine, and as well turned out as a cover girl.
``I've always had this thing for clothes,'' she admits, ``even when I didn't have any money. I could mix and match until I looked fashionable. I think being named `Best Dressed' in my '62 high school yearbook was a highlight.
``My crew kids me about the number of costume changes I have on the tour. I think audiences like to see you in glamorous gowns, costumes, jewelry; so I don't think a new dress every 10 minutes is too much!''
Today, when Ross tours, it's always with family. Her two sons, Ross, 2, and Evan, 9 months, are there with bassinet, nannies, and Ross's ``Vroom-Vroom,'' the name he has given to his car bed.''
When she played Reno, both Diana's and Arne's children came along, making it eight youngsters, plus parents, maids, crew, and band. ``We're a circus,'' she says with a cascade of laughter.
Asked if raising her second family is different from the first, she says, ``When I had my three girls, my mother was alive. She'd take care of them whether at home or on a tour. I had such a secure feeling. If they weren't with me, Mom had her watchful eye on them.''
That part is different, because her mother passed away a few years ago, and Naess's mother is 82. Diana's three daughters - Rhonda, Tracee, and Chudney - by her first husband, manager Robert Silberstein (known professionally as Bob Ellis), are teen-agers. Her two sons by Naess are always with her.
WHY does she work so hard? Why is she driven? ``I remember reading a quote from Helen Keller: `Life is either a daring adventure or nothing.' It would be easy for me to do nothing but repeat the '80s, but I want my executive position with Motown to be hands-on. I hope to put back into the music business some of the knowledge I've gained, especially guiding younger talents as they start their careers.
``I've always had such big dreams. Even as a little girl I would sing and dance for my family or for anyone who would listen.''
In 1960, the trio that would become the Supremes won its first talent contest across the border from Detroit in Ontario, Canada. In 1961, after they had finished high school, Motown chief Barry Gordy agreed they could record their first single, ``I Want a Guy.'' In 1964, ``Where Did Our Love Go?'' became their first of 15 million-selling singles. The next year they were on the cover of Time magazine. In 1970, the Supremes gave their farewell performance at the Last Frontier in Las Vegas, and Ross launched her solo career with ``Ain't No Mountain High Enough.''
``I still dream,'' she says. ``I'd like to do more movies. I would love to do the Josephine Baker story, and I have invested a lot of my own money researching her life. ... If someone else does it, I'd still like to have something to do with the project.
``I'm always challenged by something new; I feel charged and alive. Even today, whenever I record a new song, I get excited, I think it's the best I've ever done. It's exhilarating to stand in the spotlight before a live audience. It's not just their reaction but that the performance represents my total effort.
``There are ways of dealing with the world that invite energy in. You have to be excited by the things you don't know. This keeps you constantly stimulated, on a learning spree with life.''