The actress and model - who previously dated Prince Harry - stars in the video for James' new single 'Naked' and the former 'X Factor' winner has revealed he felt a ''spark'' while they were on set together.
James shared: ''There was chemistry there. I have genuine aspirations of being an actor.
''In order to convey that on screen, you've got to have those thoughts and embody that feeling.''
However, James conceded that nothing is likely to come of their ''spark'' because Cressida already has a boyfriend.
Speaking to The Sun newspaper, the 29-year-old singer explained: ''I was trying to have a spark with her and we had a spark. It was good. She was really professional, really talented. I believe she's got a boyfriend.''
In the video, James plays a talk show host, while Cressida is a star being grilled by him until she breaks down in tears.
Cressida, 28 - who dated Prince Harry for two years between 2012 ad 2014 - shares an emotional embrace with James at the end of the video.
The blonde beauty is currently believed to be in a relationship with Harry Wentworth-Stanley, who she met while they were both studying at Leeds University.
Despite this, James flirted with Cressida on set by teasing her about her posh accent.
The 'Impossible' singer said: ''She sounded posh. I was having a bit of crack with her. My banter's like, 'Oh you're a royal are you?'''
James hired Cressida to star in the video for 'Naked' the same week Prince Harry announced his engagement to former 'Suits' actress Meghan Markle.
And he believes the timing of that announcement has worked to his benefit.
He said: ''The timing was perfect for us, we get a little bit of extra press.
''I had no idea. I've met Harry and Will and Kate at a mental health dinner one time and thought they were super cool. I spoke to Harry in depth about mental health and thought, 'Lovely guy'.
''Obviously I know of the royal family, but I don't know about Miss Markle, I've recently become educated on the whole thing but Cressida auditioned for the video and she smashed it and that's why she did it.''
Once a fire fighter, always a fire fighter.
Today (September 14th) marks the 25th anniversary since the album's 1993 release.
Labrinth has teamed up with Sia and Diplo to form a new supergroup: LSD.
The Struts teamed up with Kesha for a red and gold themed music video as part of their collaboration on 'Body Talks'.
Sometimes actors are not acting.