Williams was a huge fan of Colton's rendition of Beyoncé's 'Halo' when he joined Gary Barlow in LA to judge the Boys category. He told his bandmate afterwards: "I'll fall out with you, Gaz, if you don't give him good marks every week."
Williams and Colton have kept in email contact since their meeting in LA and the pair have been talking about songwriting together.
The Liverpool singer, who was eliminated from X Factor last night, told DS: "Robbie's just been really supportive and trying to help me where possible.
"I'm really passionate about songwriting and he's been helping me with that, helping me be the best that I can and demonstrated on a few of his own tracks how he wrote them. He's definitely, definitely helping me and he's a lovely guy."
Colton added: "We kept in touch throughout the whole process and he's definitely a friend as well."
The 22-year-old former biscuit factory worker also claimed that the highlight of his X Factor experience has been teaming up with mentor Barlow.
"He's an absolute gentleman and I'm going to see him today because he wants to speak with me," said Colton.
"Gary has been a massive support for me and we'll definitely continue working together after the show."
> 'X Factor' Craig Colton exit interview