Newly-released pictures show Mason performing in front of Nick and special guest Mark Ronson at Judges' Houses, which was held at Cotswolds.
It was confirmed last week that Mason earned a place at Nick's Judges' Houses after Tom Bleasby quit - but it was a controversial choice.
Tom gained, lost, then gained a seat again during the all-important Six Chair Challenge, but just a day after his challenge aired on TV, he decided to bow out of the competition.
Tom said he did not feel "vocally ready" to progress further in the competition.
His exit meant there was a spare space to fill, as six contestants are chosen for Judges' Houses, and in the following days, Nick confirmed that he would be bringing back Mason.
However, Mason's Six Chair Challenge performance was far from smooth sailing. Mason annoyed Simon Cowell after his performance as he complained about the amount of airtime he had been given.
Mason said that he only had "47 seconds" of airtime on his first audition, compared to other contestants who had "10 minute slots".
Head judge Simon branded Mason a "complete a*sehole" and told him he had no right to insult X Factor and its producers.
"You're five seconds away from getting thrown off this stage," Simon told Mason. "If you've got a problem then just go."
Mason dropped his mic and left the stage, and once he had gone, Nick said he would have got a seat if it hadn't have been for his outburst.
Speaking of his decision to bring back Mason, radio 1 DJ Grimmy said: "After Tom decided to leave the show, Mason was the person I wanted to bring back."
"Yes he was difficult at the 6 Chair Challenge, but people with an artistic temperament can be difficult. He's talented and in previous auditions excited us Judges. Sometimes a challenge is interesting."
Mason said of his comeback: "I appreciate Nick inviting me back on the show," he said. "And even more so, I appreciate the fact he understands what I am trying to achieve... challenge accepted."
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