Calling all ABBA fans, secret and otherwise... this is one NOT TO BE MISSED.

With Agnetha Faltskog's glorious return to the music scene, the time is right for this tantalising glimpse into the private world of the 'girl with the golden hair', the dazzling but shyest member of one of the world's most enduring pop groups.

abba
Benny, Friday, Agnetha, Bjorn - one of Sweden's biggest success stories

Her sweet manner belied her ambition which saw her, at 15, become a successful pop artist in her own right, with self-penned songs that propelled her into the charts, and later into the arms of fellow Swedish young star Bjorn Ulvaeus. They joined forces with another couple, Benny and Frida, and hence ABBA was born.

The next decade we saw them charting happiness, and misery to the tune of 370 million record sales, and global fame. Going behind the scenes of hits like 'Dancing Queen', the most moving part of this documentary is when Agnetha and Bjorn, interviewed separately, talk about the song 'The Winner Takes It All', the soundtrack to their divorce which became an enduring global ode to heartbreak.

At risk of teaching ABBA fans to suck eggs, and boring non-fans, I won't go on, but it's all here, with contributors Benny and Bjorn both speaking admiringly of Agnetha's own song-writing abilities. We don't hear from Frida, although Agnetha is at pains to say that reports of their disharmony are exaggerated.

Nor do we hear much about her personal life since ABBA, including the strange episode when her ex-boyfriend was issued with a restraining order after he was arrested for stalking her. What is clear is that Agnetha is neither a freaky recluse, nor a neurotic Sunset Boulevard character living out a strange existence on her lonely island. She is just a very successful, talented person who doesn't like live performing and has plenty of family, and money, to keep her occupied...

Until now. The documentary brings us right up to date, with her return to the studio for her latest album, which includes a duet with our very own Gary Barlow. The sight of him meeting her for the first time - AFTER the recording - is slightly cringeworthy, with him begging her to perform live, and her crying off, but you can't blame the man. There's only one Agnetha, even if she doesn't feel any need to prove it.

'Agnetha: Abba & After' is on tonight at 10.35pm, BBC1.

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  • Abba, the top-selling Swedish group

    Abba, the top-selling Swedish group, on stage at Wembley Arena during their concerts which mark the group's first appearance in Britain for three years.

  • Anna and Frida perform "Waterloo" in rehearsals

    Anna and Frida of the Abba group singing Sweden's entry, "Waterloo", during a dress rehearsal in Brighton for the Eurovision Song contest.

  • ABBA Royal Albert Hall

    Agnetha Faltskog (left), Bjorn Ulvaeus and Annifrid Lyngstad during the concert by Swedish pop group ABBA at the Royal Albert Hall.

  • ABBA disc

    A trophy presented to ABBA for celebrating worldwide sales of over 360,000,000 on the stage to celebrates 5th year anniversary of West End Musical Mamma Mia at the Prince Edward Theatre in central London.

  • ABBA

    17th NOVEMBER : On this day in 1974 pop group ABBA begun their first tour of Europe. The four members of Swedish pop group "Abba" . From left to right: Benny Anderson, Anni-Fryd Lyngstad, Anna Falkstog and Bjorn Ulvaeus on their way to a press conference at Crockford's Club in London Carlton House Terrace. *The group were in Britain to attend the premiere of their first film, ABBA - The Movie, at the Warner West End 2 Cinema in Leicester Square. Much of the film is about their Australian tour.

  • ABBA : 1974

    1/4/74 : SWEDISH POP GROUP "ABBA" IN LONDON FOR A PHOTOCALL TO PROMOTE THEIR SONG "WATERLOO" WHICH THEY WILL ENTER INTO THE EUROVISON SONG CONTEST IN BRIGHTON. FROM LEFT TO RIGHT: BENNY ANDERSSON, FRIDA LYNGSTAD, ANNA FALTSKOG AND BJORG ULVAEUS

  • Abba congratulate each other

    The pop group Abba congratulate each other in Brighton, after winning the Eurovision Song Contest for Sweden with "Waterloo", sung by the girls, Annifrid Lyngstad (Frida), second left, and Agnetha Faltskog (Anna). The other group members, Benny Andersson, left, and Bjorn Ulvaeus, composed the song.

  • Swedish pop group Abba

    Swedish pop group Abba meet a mounted policeman as they relax in Brighton, after their victory in the Eurovision Song Contest. From left: Agnetha Faltskog (Anna), Bjorn Ulvaeus, Benny Andersson and Annifrid Lyngstad (Frida). The men composed the winning song, "Waterloo", which was sung by the girls.

  • Abba - Heathrow Airport - London

    Swedish pop group ABBA (from left) Benny Andersson, Annifrid Lyngatad, Agnetha Faltskog and Bjorn Ulvaeus at Heathrow Airport.

  • Music - Eurovision Song Contest 1974 - Brighton

    SWEDISH POP GROUP "ABBA" AT THE EUROVISION SONG CONTEST IN BRIGHTON IN WHICH THEY WON WITH THEIR SONG "WATERLOO". FROM LEFT TO RIGHT: BJORN ULVAEUS, AGNETHA FALKSTOG, ANNIFRID LYNGSTAD AND BENNY ANDERSSON

  • Abba

    Swedish pop group, ABBA. (l-r) Annfrid, Benny (front) Bjorn (back) and Agnetha.

  • Abba

    ABBA's Anna, Bjorn, Frida, and Benny after they won the Eurovision Song Contest with "Waterloo".

  • ABBA & Princess Margaret

    Princess Margaret with four members of the Swedish pop group "Abba" afther she had presented them with the Carl-Alan group Award for 1977 at the Lyceum Ballroom in London. (l-r) Anni-Fryd Lyngstad, Benny Anderson, Bjorn Ulvaeus and Anna Falkstog.

  • Music - ABBA - European & Australian Tour - Gothenburg, Sweden

    ABBA perform on stage in Sweden. (l-r) Bjorn Ulvaeus, Anni-Fryd Lyngstad and Agnetha Faltskog

  • Music - ABBA - European & Australian Tour - Gothenburg, Sweden

    ABBA wish their fans goodnight after performing in Sweden. (l-r) Bjorn Ulvaeus, Agnetha Faltskog, Anni-Fryd Lyngstad and Benny Anderson

  • Music - ABBA - Royal Albert Hall, London

    Bjorn Ulvaeus, Agnetha Faltskog, and Frida Lyngstad, right, from Swedish pop group ABBA on stage at the Wembley Arena, London.

  • Music - ABBA - Wembley Arena, London

    Agnetha Faltskog, left, and Frida Lyngstad, female members of Swedish pop group ABBA on stage at the Wembley Arena, London.

  • Music - ABBA - Wembley Arena, London

    Bjorn Ulvaeus, from Swedish pop group ABBA on stage at the Wembley Arena, London.

  • Music - ABBA - Wembley Arena, London

    Agnetha Faltskog, from Swedish pop group ABBA on stage at the Wembley Arena, London.

  • Music - ABBA - European & Australian Tour - Gothenburg, Sweden

    ABBA perform on stage in Sweden. (l-r) Agnetha Faltskog and Anni-Frid Lyngstad