The 'Sight Of You' singer said that Arthur, who will compete to be crowned the winner of the talent show this weekend, says that she's "hot".
Tulisa told reporters: "He tells me I'm hot all the time, to my face," adding: "That's not why I'm a big fan!
"He's just real. He'll be like, 'You alright T? Looking fit today', and I'm like, 'Thanks, James, cool'."
The former N-Dubz member went on to say that she has always backed the Middlesbrough-born contestant.
"I love James, he is the reason I wanted the boys category," she explained.
"He is real as a person and I connect with him more than any other contestant. He is honest and real with his music too."
Arthur is up against Jahmene Douglas and Christopher Maloney in this weekend's X Factor final, which airs tomorrow (December 8) at 8pm on ITV1.
Watch Tulisa and Louis Walsh discuss the X Factor final with Digital Spy and reporters below: