N-Dubz star Tulisa had been accused of offering to help introduce an undercover reporter to an alleged drug dealer - something she strongly denied - and she walked free from court last month when the judge dismissed the case against her.
Speaking to Kate Garraway on ITV's Lorraine, the Union J boys said they thought it was "a shame" that people had made assumptions about the singer from the bad press she had received.
Following the collapse of her trial, Tulisa starred in a documentary, Tulisa: The Price Of Fame, that saw cameras follow her for 13 months.
Union J singer Josh Cuthbert said he had watched the documentary and felt it was nice for the public to finally see things from Tulisa's point of view.
He said: "It's nice to hear her story... whenever we saw her at X Factor she was a lovely lady, she'd always make the time to come and see us."
Fellow band member Jaymi Hensley revealed he tweeted Tulisa after the documentary aired to show his support. He told Kate: "I tweeted her saying it was really nice to see the Tulisa that we know and love...
"People that necessarily wouldn't have known her before but saw all this bad press she got and made an assumption, to see all the positive feedback she got, I think she did [the documentary] in exactly the right way.
"I think it was sad to see someone completely be ruined."
Josh and Jaymi, along with bandmates JJ Hamblett and George Shelley, met Tulisa when they entered The X Factor back in 2012.
Although George originally entered as a soloist, all four boys initially didn't make it past boot camp.
With the arrival of George in the band, the boys were given a second shot at the competition when they replaced fellow X Factor contestants Rough Copy to join Louis Walsh in Las Vegas for the judges' houses round. They then went on to reach the final four in the live shows.
Speaking about their mentor on the show, Louis, JJ said: "He was a big part of our life for a long time and he still is. He was like the fifth member [of our band] so we love Louis!"
JJ revealed he is very much looking forward to having Geordie beauty Cheryl Fernandez-Versini back on the panel and, chatting about this year's judges, he said: "I think it's going to be amazing this year and obviously Simon the King is back and then you've got Mel B, she was amazing on the Australian X Factor and she's quite feisty as well so I think it's going to be really cool to see how they're all going to get along."
Us too, JJ. Us too!
The boys appearance today comes as they are busy promoting their new single 'We Live Forever'.
As they gear up for its release later this week, George told Kate they were feeling the pressure for chart success as the track is their "favourite single they've released so far".
'We Live Forever' is released this Sunday 17 August.
Reveal is now on Google Plus! Join us here for the latest pictures, fashion and celebrity news!
Watch the video for Union J's new single 'We Live Forever' here: