As a segment for James' first week as the new host of The Late Late Show, Mariah joined the comedian and presenter in his Range Rover for a sing-along.
In a video shared via YouTube, James is seen driving along with Mariah in the passenger seat and he suggests they put on some music. But unbeknown to Mariah, James puts on one of her classics, 'Always Be My Baby'.
Their karaoke session is amazing, and Mariah even lets James take the lead vocals!
We also love how Gavin & Stacey star James was so in the moment with his dancing and singing.
The pair don't just sing, however, as mum-of-two Mariah also tries out her best British accent. But intent on not letting the good fun end, James soon puts on Mariah's other tracks including 'Vision of Love' and 'Thirsty'.
Can you imagine hanging out with Mariah?!
Sharing the video with fans via Twitter, James said: "Me and @MariahCarey in the first carpool karaoke!!!! She's such a great sport, hope you enjoy."
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