Rebecca Tyrrel: Who knew the dark-haired one from Abba has had quite a life? Her boyfriend is WH Smith...

Who knew that if the dark-haired one from Abba ever married her boyfriend, WH Smith, also known as Viscount Hambleden, being a social climber is absolutely the last thing she could be accused of? In fact, becoming a viscountess by marrying a stationery heir would mark a sharp descent in social status for a woman whose present title is Her Serene Highness, Princes Anni-Frid Synni Reuss.

Frida Lyngstad, as she is more commonly known, has had quite a life. Conceived in occupied Norway in 1945 in the last days of the Second World War, by the time it was over her German-soldier father had been evacuated back to the Fatherland. Her teenage mother fled with her across the border into Sweden, to avoid ostracism or worse for consorting with the enemy, but when she died of kidney failure, Frida was raised in Sweden by her grandmother, who taught her folk songs. By the time the 22-year-old won Sweden's version of New Faces, she had two children of her own by musician-husband, Ragnar Fredriksson.

She divorced first him, as she later did Benny Andersson (the marital history book on the shelf is always repeating itself), with whom she, Agnetha and Bjorn formed Abba, and in 1992 had a third crack at the nuptials with German nobleman Prince Heinrich Ruzzo Reuss. But he died of lymphoma in 1999, the year after her daughter from the first marriage was killed in a car crash.

When William Henry Smith, who at 57 is a decade her junior, asked her "Voulez vous?", she laid all her love on him. The two now live in Zermatt, Switzerland, where her peaceful seclusion was interrupted only by a legal case brought against a Buddhist monk who insisted that the £4.5 million she had given him was not a loan, as she claimed, but a donation. The monk was the winner in court and took it all, but with her wealth estimated at £100 million, and the Viscount not short of a few quid, there is no pressure on her to return to the recording studio. Which is as well, since she insists that she has no desire to revive her career.

So extraordinary has been Her Serene Highness's life that it deserves the sort of musical biopic which would, with the right sixty-something actress in the lead, be an instant classic. It is a shame that Meryl Streep would never demean herself by starring in an Abba-related movie.