Forget Mamma Mia 3 – give us Mamma Mia 1.5 and more Meryl Streep

Explaining that "there’s meant to be a trilogy", Craymer added that Universal Pictures are on board. ABBA star Bjorn Ulvaeus has also said he would be interested if the right idea arose. All good news, which means confirmation is beginning to look likely.

But with discussion ongoing over another comeback, what could the movie plot involve this time around?

There was a substantial gap between the first film and 2018 sequel Here We Go Again, not just in real time but in the characters’ world too. The missing years were only vaguely referenced, so perhaps we could be treated to the untold story rather than a direct follow on?

There's plenty of potential here: the main story could see Donna reminiscing about being a young mother while missing her daughter. The scenes could then switch back and forth between Donna, her younger self and Sophie (Amanda Seyfried) who set off on her travels with boyfriend Sky (Dominic Cooper) at the end of Mamma Mia. This would catch us up on Sophie and Donna’s lives, with the added bonus of treating us to more of the flashbacks in which the young Donna was played so brilliantly by Lily James.

Continuing to explore Donna’s memories could show us how she first set up the hotel as her livelihood, what with it remaining very much a part of the scenery across both films, while in the present day, we could also find out more about Donna’s marriage to Sam (Pierce Brosnan) following their spontaneous wedding.

As for Sophie and Sky, things were a bit strained between them at the beginning of Here We Go Again, apparently due to Sophie’s dedication to renovating the hotel in her mother’s honour and Sky feeling that this was putting their life together on hold. Again, opting for a "midquel" over a sequel would allow us to see their relationship in more detail before tragedy struck, and exactly what led them to that point – much more interesting than the pair playing family families, or experiencing another bump in the road.

Among the ensemble of supporting characters there just has to be time for more of Rosie too, played by the legendary Julie Walters. Rosie very memorably got together with Donna’s ex Bill at the end of Mamma Mia, only to have split with him by the time we next saw them due to his wandering eye.

Although they later reunited, there would surely be great entertainment in seeing how their issues played out during the gap, after the attention the pair’s break up was given – and Mamma Mia fans know that every Rosie scene is guaranteed to be gold.

Most importantly, though, exploring the lost years would mean a welcome return for iconic actress Meryl Streep. She only had a brief cameo as the spirit of Donna in the second movie due to the character’s off-screen death, which was said to have taken place the year before.

How Donna passed away is a mystery; but whether those details are revealed or not there is still plenty of room to fill in the blanks from that unknown period of time.

It’s not just us who want to see Meryl Streep back with her Mamma Mia family. Alexander Skarsgård, son of Stellan Skarsgård who stars as Bill, has claimed he would love a role in a future film if it came with the chance to star with Meryl again, who he worked with on Big Little Lies. Perhaps he could appear as one of Sam’s grown up sons on a visit to the island, as they haven’t been seen before now?

Happily, several cast members voiced their enthusiasm for the idea of making a third film when Here We Go Again was released, including Lily James, Pierce Brosnan and Christine Baranski (Tanya) – but any new instalment should include the entire original cast, Streep included – and the only way to make that happen is to go down this route, given that the characters were all present in the sequel.

There is definitely potential for a multilayered story within this time frame. So if the hit musical turned film franchise is heading back to a screen near us in the future, forget Mamma Mia 3 – the campaign for Mamma Mia 1.5 starts here!

Mamma Mia: Here We Go Again is streaming now on Netflix – check out our lists of the best TV shows on Netflix and the best movies on Netflix, or see what else is on with our TV Guide