The short teaser sees the reunited groups discuss their careers, relationships and fallouts, and it proves to be an emotional time for some as they delve into the rows and fights that tore their groups apart.
It seems newly-formed group 5th Story attempt to define their role within the music industry, as they discuss whether they are a boy band, vocal group or man band.
Gareth Gates, who rose to fame as runner-up on Pop Idol in 2002, said he found it "daunting" having to transition from being a solo star to now working as part of a group.
Meanwhile, the reality of coming back into the limelight sinks in for Girl Thing's Jodi Albert, who reveals: "Out of all the reunions in all the world, I never saw this one coming."
Elsewhere, Damage speak about their fallout with lead singer Coree Richards, who left the group and went solo. Coree wasn't pictured with his Damage bandmates as they kick-started rehearsals this week, but it's clear that he's keen to give his side of the story.
The second series of the popular reality show will follow the groups as they reunite and prepare for a tour. Throughout, it will feature candid interviews from each member as we delve into their lives and explore what happened after they slipped out of the charts.
The Big Reunion is due to return to ITV2 next month.
Which band are you most looking forward to seeing? Tell us below, as the best comment from across the website each week wins £50!