The 'Live While We're Young' group, who were themselves formed on the ITV reality show in 2010, revealed that they are fans of Louis Walsh's acts.
"The boybands are really good," One Direction's Harry Styles told Heatworld. "I think its good that there are two boybands because a lot of the time I don't really think they want to put two of them through.
"I think they are both really great and talented and they showed that [on The X Factor]."
Styles's bandmate Louis Tomlinson agreed, describing Union J and District3 as "such nice guys as well".
It has been reported that Styles recently gave Union J member George Shelley tips on how to be "a hit with the ladies".
Photo gallery - The X Factor's second Live Show in pictures:
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