Abba star Bjorn's shock admission: 'I'm battling long-term memory loss'

Bjorn Ulvaeus cannot even remember winning the Eurovision song contest in 1974 with one of their best-known songs, Waterloo.

It was the victory at the contest in Brighton that propelled the Swedish group to international stardom.

Battle: Abba's Bjorn Ulvaeus, pictured here with Anni-Frid Lyngstad at the London premiere of Mamma Mia! in London last week, has revealed he's seeking medical help for memory loss

'It is like I was not even there,' said the 58-year-old father of four. Ulvaeus composed the music for the Mamma Mia! stage musical with fellow Abba star Benny Andersson and makes a brief uncredited appearance in the film, which stars Meryl Streep, Pierce Brosnan and Colin Firth.

The movie has sparked an Abba revival but Ulvaeus says he simply cannot remember chunks of his life.

He has even turned to hypnosis in an attempt to find a cure.

Memorable moment: Bjorn says he can no longer recall Abba's performance at the 1974's Eurovision Song Contest

The songwriter, who divorced the band's blonde songstress Agnetha Faltskog in 1980 and is now married to Swedish music journalist Lena Kallersjo, has studied old photographs and video to try to remember his life.

Abba enjoyed a string of hits including Money, Money, Money, and Dancing Queen before splitting in the mid 1980s. They sold more than 400million records worldwide.

Mamma Mia! The Movie, released last week, has already taken more than £7.6million in the UK, more than any other musical in its opening week.

Remember when: Bjorn struggles to recall the best - and worst - Abba moments

Thank you for the music: The original cast of Abba,  Bjorn Ulvaeus, Benny Andersson, Agnetha Faltskog and Anni-Frid Lyngstad