LONDON (AP) ― Four decades on from the flares, fame and fabulousness, the members of ABBA say they have no regrets ― not even about the clothes. 

Members of the Swedish supergroup marked 40 years since their international breakthrough hit “Waterloo” on Monday with a party for hundreds of guests at London’s Tate Modern gallery.

Bjorn Ulvaeus said he felt “extremely proud and humbled” by decades of success that includes hit records, the stage and movie musical “Mamma Mia” and a Stockholm museum dedicated to the band.

And Frida Lyngstad said she was proud of ABBA’s ultra-’70s look of big boots and spangly jumpsuits, documented in a new photo book about the band. 

“It was our youth, it was our time, and we decided how we wanted to dress ourselves onstage,” said Lyngstad. “And it was fun.”

She said some performers “are even more courageous nowadays, if you think of Lady Gaga, for example.”

Lyngstad said she could not explain the global success of ABBA, which rocketed when the band won the 1974 Eurovision Song Contest with “Waterloo.” The quartet’s blend of poppy melodies, lush harmonies and slick arrangements helped them sell more than 400 million records around the world.

“We never had a formula,” Lyngstad said. “We just did what we loved the most. And the great thing was maybe that the four of us met and started to work together the way we did. Two great songwriters, Bjorn and Benny, together with Agnetha’s and my voices.”

The foursome eventually fractured, with the band’s two married couples ― Lyngstad and Benny Andersson, Ulvaeus and Agnetha Faltskog ― divorcing.

But Ulvaeus said the four of them recently met up, and “the chemistry is still there.”

“We bonded instantly,” he said.

So are they tempted to make fans’ wishes come true with an ABBA reunion?

Lyngstad laughed. “No,” she said.