Around 75 acts are left in The X Factor as we head for the six chair challenge but we've not met all of them yet.
Some hopefuls have seen their auditions and bootcamp performances cut from the telly meaning we know almost nothing about them!
Here we profile five of X Factor' mystery performers who are still in with a shot of winning this year's competition.
17-year-old Scottish singer Caitlyn performed I See Fire at her arena audition to score a full set of yeses from the panel. As yet we've only seen a tiny glimpse of her during the bootcamp performances when she was hidden behind girl group Alien. You can follow her on Twitter @caitlynvanbeckx.
22-year-old Sophie (main picture, above) is a mum of one from Croydon. Her first audition didn't quite go to plan performing THREE times for the judges. She eventually got a yes however and is now through to the six chair challenge. You may have seen her getting stuck in the middle of Monica Michael and Princess Diamond's bootcamp row. You can follow Sophie on Twitter @sophieplumb100.
Danny auditioned for The X Factor this year with a cover of Michael Jackson's Black Or White. While the try out was cut from air, he's since uploaded his version of the song which you can watch below. You can follow Danny on Twitter @iamdsharp.
Girl group Decibellas are a five piece made up of Lily, Sophie, Harley, Emily and Alice. So far they've appeared only briefly during the bootcamp group stage, performing alongside Kiera Weathers. Follow the girls at @Decibellas_UK.
Ryder - aka the @ryderlads on Twitter - are a boy group made up of Dan, AJ, Sandy, Aaron and Rhys. We really don't know much about them at all other than that their name appears on the list of acts through to the six seat challenge. We don't even have a picture! Fortunately, the guys have just launched a YouTube channel and you can check out a recent cover of theirs below...
With three weeks' worth of six chair challenge footage coming our way, maybe they'll finally grab some air time!
Remember to check out the full list of X Factor 2015 contestants here!