Marvin Humes, Aston Merrygold, Oritse Williams and JB Gill broke a million hearts earlier this year when they announced they'd be parting ways at the end of 2013 following a farewell album and tour.
The boys played their last concert as a foursome at London's O2 Arena on Sunday night (21 December), attracting a sold out crowd that included famous friends and family.
Among those watching the show were 1D's Niall and Liam, who both admitted they welled up at the end.
Niall tweeted: "Jesus! That was an emotional one last night! tears were flowing all round! congrats t the jls lads. What a career! Love u boys (sic)."
He later posted a picture of JLS sharing a group hug on stage, saying: "That's when I started ballin!"
Liam, meanwhile, tweeted: "Had an amazing night watching @JLSOfficial , amazing guys , brilliant music!"
When a fan asked if he'd shed a tear, he replied: "A couple, sad there going, they were the ones i supported after not getting through the first time in xfactor (sic)."
JLS and One Direction share something very big in common: they both found fame on X Factor and, despite neither band winning their series, went on to achieve huge success in the music industry.
After finishing runner-up to Alexandra Burke in 2008, JLS went on to achieve five number one singles and release four albums.
In a statement announcing their split in April, they said: "We will always remain brothers and friends and we will always be your boys. Thanks to all of you guys, your support, your dedication and you have changed our lives forever. We wouldn't be where we are today without you."
Also at last night's JLS show were Marvin's wife Rochelle and their baby daughter Alaia-Mai, and another X Factor alumnus, Olly Murs, who tweeted: "Couldnt be anywhere else right now than right here @TheO2 to watch @JLSOfficial my mates on their last show! Crazy! Emotional night fellas x."
Watch JLS' final music video for 'A Billion Lights' below:
JLS: our favourite moments in pictures -
Copyright: WENN ITV