Appearing on ITV's This Morning on Friday (16 September), singer-songwriter James revealed the former Pussycat Doll has stayed in contact with him since the 2012 show.
"She's a mega star and for her to still reach out to be on a regular basis is a testament to her character," said James, adding: "I love her."
James is also still friends with fellow contestant Rylan Clark-Neal, who was also mentored by Nicole in her Boys category.
"I love him to bits," said James. "He's a really amazing guy and his achievements since the show have been very inspiring."
Rylan's gone on to present Big Brother's Bit on the Side, his own Channel 5 chatshow, a showbiz slot on This Morning and more, as well as releasing an autobiography.
James, meanwhile, has just returned to the limelight with brand new single 'Say You Won't Let Go', which has already been shooting up the iTunes chart.
He admitted on This Morning that he needed time off after melting down in the public eye. He'd struggled to cope with his fame and success post-X Factor, leading to behaviour that he's "embarrassed" to look back on.