Abba have released the third new track, 'Just A Notion', from their upcoming comeback album, 'Voyage'.

The Swedish pop icons - Agnetha Faltskog, BJORN ULVAEUS, BENNY ANDERSSON and Anni-Frid Lyngstad - have followed up 'I Still Have Faith In You' and 'Don't Shut Me Down', their first new music in almost 40 years, with the outtake from 1979's 'Voulez-Vous'.

Bjorn has admitted it's still a "mystery" as to why the upbeat tune wasn't included in the final track-listing in the end.

The 76-year-old songwriter explained: "Wikipedia says this track was recorded in September 1978, which sounds about right. That puts it in between 'ABBA' the Album and 'Voulez-Vous', and it would have been included in the latter had we not decided against it. Why did we decide against it? In hindsight, I don't have a clue. It's a good song with great vocals. I know that we played it to a publisher in France and a couple of other people we trusted and as far as I can remember they liked it very much. So it's a mystery and will remain a mystery."

It features the original vocals the four members laid down in Stockholm in 1978, with new drums and guitars.

The 'Waterloo' hitmaker continued: "Now Benny has recorded a new backing track to which we've added drums and guitars, but all vocals are from the original 1978 tracks. In a way, it demonstrates what we plan to do with ABBA Voyage in 2022. There, we will have a live band playing, but all vocals will be from the old recordings.

He added: "'Just a Notion' is a ridiculously happy song and hopefully it will cheer you up in these dark times!"

The 'Dancing Queen' stars have also announced further tickets will be made available for their upcoming avatar tour.

The additional tickets for 'ABBA Voyage', which will take bookings to December 4, 2022, will be on sale from 10am on November 3, two days before the album is released on November 5.

Tickets will be made from abbavoyage.com, with a pre-sale for Amazon UK customers that pre-order a physical format of the new ABBA album available from 10am Monday November 1 and a priority booking window for ABBA Voyage database subscribers from 10am November 2.

ABBA will be performing digitally as 'Abbatars' with a live 10-piece band next year as part of the ‘ABBA Voyage’ run, and Bjorn recently insisted this type of concert means the run could go on forever.

He said: “Abbatars never tire. They can do 10 shows a day. No private jets. No riders. No worries about voices."

The ‘Thank You For The Music’ hitmakers have teamed up with an 850-strong team from Industrial Light & Magic - the company founded by George Lucas – to create digital versions of themselves for the concert, using months of motion-capture and performance techniques.

The ‘Voyage’ concert experience will open on May 27 2022 at the ABBA Arena, which is a state-of-the-art 3,000 capacity arena located at Queen Elizabeth Olympic Park in London, and will feature their new music.