The presenter joined Fleur on stage as she continued her assault on the US on Wednesday (25 May) night.
The 2014 'X Factor' runner up appeared as a musical guest on 'The Late Late Show', and during her performance James couldn't resist showing off his moves as he joined in with her troupe of dancers.
And we have to admit it, he nailed it.
It is Fleur's second appearance on US TV, as she attempts to launch her career Stateside.
Earlier in the week, she performed on the final of the American version of 'Strictly Come Dancing', 'Dancing With The Stars', and was met with a rapturous reception.
She's also scheduled to appear on breakfast programme, 'The Today Show', later this week.
'Sax' charted at number three in the UK charts when it was released in November last year, and has also achieved success in Mexico, The Netherlands, Costa Rica and Eastern Europe.
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