Pop reunions: You're back? We didn't know you'd been away!

From the Stone Roses to the Spice Girls, it seems pop reunions are something we've had our fill of. Or have we? Make way for the second wave. Except that we're now onto the B-list groups, and the reunions-before-they've-even-split-up. It might be quite hard to believe, but one of 2012's most successful tours was Steps' Ultimate Tour. Yes, that all-miming, dancing machine who predated Crazy Frog in the current trend for cheesy, ringtone-friendly pop tunes. While it might be difficult to digest that, come the new decade, Steps fans would once again be braying for "One For Sorrow" and doing that dance to "Tragedy" in matching pink Stetsons, it may be harder to contend with the fact that they are leading a second wave of B-list pop reunions.

No sooner had they left arenas across the country covered in silver tickertape and smelling of dry ice, than the news came to us that the bands who were residents of those Now! compilations in the late 1990s were all returning. In the new year we will see a six-part ITV2 show called The Big Reunion which will find an endless trail of cheesy pop stars (Atomic Kitten! ,5ive!, B*Witched!, 911!, Liberty X!, the Honeyz!) all reuniting for the first time since they broke up.

In fact, the concept of the "reunion" has got everyone so hot and bothered that bands who've not yet split up have made gestures towards getting back together. Rather optimistically, Niall Horan of One Direction recently stated: "We want to be like Take That… and take 10 years and then come back."

Girls Aloud, who have been silent as a band since 2009 and who have not formally split but had been widely thought to be separated in all but name, have burst back into our consciousness with a new single ("Something New"), a greatest hits album (Ten, featuring four new songs), an arena tour for 2013 and a tell-all reality show. Although billed as a "celebration of their ten years together", in her recent autobiography Cheryl Cole let it slip that "that's it" for the band. So why does this Girls Aloud re-grouping feel less like a "final hurrah" and more like a nostalgic reunion? And why is it even being billed as a genuine reunion? And why are one the biggest boy bands on the planet talking about a future where they've broken up, and then got back together a decade later?

In the cash-strapped music industry, reunions feel like something approaching a sure thing, but when there's a reunion before they've even split, as in the case of Girls Aloud, they are potentially shooting themselves in the foot, diluting the excitement of a true reunion.

In the 2012 model, a tell-all documentary has come to be a vital prop of the B-list pop reunion. Take That set the template back in 2005 with their reunion documentary, Take That: For the Record. "To hear [Take That] talk so candidly about the break-up, drugs, depression, suicidal thoughts and groupies was not what anyone would have expected from the biggest boy band of them all," director David Notman-Watt says. However, the pièce de résistance was the final scene in which the five members were due to meet for the first time since Robbie Williams left. Gary Barlow, Mark Owen, Howard Donald and Jason Orange all turned up to a country mansion to reminisce over bottles of Merlot before being informed that, actually, Williams would be not be showing up at all. The unsubtle subtext – Williams was an international megastar and the rest would find it hard to be singled out in a Never Mind the Buzzcocks-style line up – stuck the knife in. Notman-Watt insists this Waiting for Godot meets Punk'd scene wasn't pre-planned.

"We honestly didn't know if Robbie was going to turn up or not," he says. "Thankfully we had thought of asking Robbie to record a message to each of the boys. They weren't very impressed. It was like a message from Big Brother." Pre-planned or not, this masterful bit of "mean TV" changed everything. So we had Boyzone's The Boyz are Back in Town, the Spice Girls' Giving You Everything, and finally back to Steps. On Steps Reunion the band were thrust into tearful confrontations and dinnertime showdowns that had depth, drama and gravitas. Girls Aloud's own documentary will show the band's rise from Popstars: The Rivals to their TV comeback at The Royal Variety Performance on 19 November, complete with all the uneasy tensions between Cheryl and bandmate Nadine Coyle.

The reunion show paired with a one-hit-wonder reunion feels like a winning device, but surely not everyone has a great, traumatic tale to unload? "For so many manufactured bands there simply isn't a story to tell," says Notman-Watt. Still, we can't help but be transfixed by the thought of One Direction's tale of hair gel, spots and how much they missed their mums coming to a small screen in 2122, can we?

'The Big Reunion' will be on ITV2 in 2013. The Girls Aloud documentary will be broadcast over Christmas