The following correction was printed in the Observer's For the record column, Sunday 9 January 2011

Our report that Abba might perform again after 30 years said Anni-Frid (Frida) Lyngstad is "the widow of a Swiss prince". There is no royal family in Switzerland. The singer became Her Serene Highness Princess Anni-Frid Synni Reuss, Countess of Plauen, after her marriage to a German prince in 1992. He died in 1999. She currently lives in Switzerland.

One of the most distant dreams of pop – a reunion of Abba – has come a step closer after the most reclusive former member of the Swedish supergroup hinted for the first time that she would consider performing with the others again.

A re union more than 30 years after Abba's last chart-topper in 1980, "Super Trouper", would have a more sedate feel than the glitter, Lycra and platform boots associated with the "Dancing Queen" foursome. Three of Abba's four members are aged 64 and 65. The youngest, 60-year-old Agnetha Fältskog ("the blonde one"), made the revelation in an interview with Swedish oldies' magazine M.

"I just feel it would be fun to meet, chat about the old days and perhaps perform together," said Fältskog in her first interview for more than a decade. She revealed that she had a bag full of "half-written songs" and would like to sing the theme of a major film.

"We would not get together again for a tour like the Rolling Stones and other old bands do. I think we would all consider a one-off reunion, maybe for a good cause," she told the magazine in an interview combined with a fashion shoot.

Abba shot to fame after winning the 1974 Eurovision song contest with "Waterloo". In an achievement that has yet to be equalled, they went on to become one of the biggest groups in pop history, even though they came from a non-English speaking country. They have sold more than 370 million albums and singles, a figure which increases every year by a couple of million.

The four performers have not worked together since 1982 when they abandoned an album project after recording six songs. Fältskog's ex-husband, Björn Ulvaeus (the other blond), has continued to work with Benny Andersson (the bearded one) in a series of business and music collaborations, including the musicals Chess and Mamma Mia. Andersson's ex-wife, Anni-Frid Lyngstad (the brunette), has a solo career, is the widow of a Swiss prince and has become an environmental activist.

The group's refusal to reunite – despite a reputed offer of $1bn (£650m) in 2000 – has left the field open for a generation of camp tribute bands. In interviews, the three other members of Abba always entertained the prospect of a reunion until Andersson ruled it out in March 2010.

In the interview published in Sweden on Tuesday, Fältskog admits she has not consulted the other members of the group, none of whom she is believed to be on speaking terms with. At their last public appearance together, at a gala opening of the stage musical Mamma Mia in Stockholm in 2005, Fältskog sat separately from the others and fled the theatre when the attention got too much.

There has been little explanation of why Fältskog became the Greta Garbo of pop. But after a decade of punishing tours and personal appearances at radio stations, the lyrics Andersson and Ulvaeus wrote for "Super Trouper" – "all I do is eat and sleep and sing, wishing every show was the last show" – were seen in Sweden as the explanation for her decision to quit. More recently, Fältskog, who divorced Ulvaeus in 1979, was the victim of a long-running stalking saga which eventually saw a Dutchman, Gert van Graaf, banned from setting foot in Sweden.

In the interview, she says: "I am uninterested in appearing in newspapers and on television. Many people think I am striking a pose – that I want to create a sense of shyness. But it's just not something I want to do. I overdosed.

"When I was 15 I became a full-time singer in a band. At 18 I made my first record. When I was 25, Abba was formed. After Abba I made three solo albums. Maybe I have been productive enough."

She adds that she still plays the piano at her home on the Swedish island of Helgö. "I would like to sing the theme tune of a big film – something like Titanic," she adds.

Reactions in Sweden to Fältskog's comments have ranged from enthusiasm to squirming.

Her appearance in M is seen as the latest coup for a magazine that calls its readers "mappies'' (mature affluent pioneering people) and has done a great deal to combat a strong ageist streak in Swedish society.

The newspaper Aftonbladet's culture editor, Åsa Linderborg, said: "I do hope Abba do not get together again. John Lennon said, 'You don't reheat the soufflé'. Some things in life are timeless, like the music of Abba. But the performers come with a sell-by date.''

Sweden's most famous entertainment writer, Andres Lokko, said a reunion would only work if it came in the form of a new album with new material. "Anything else would be sad, desperate and undignified," he explained.

"I think what speaks loudest in Agnetha Fältskog's interview is her loneliness. She needs to get out and meet some new friends."