Having the superstar in the car to sing with you, of course!
That’s exactly what James Corden, 36, got to experience recently when filming for his hit US chat show The Late Late Show.
James was joined by Mariah, 45, for Car Pool Karaoke, which is as fun as the title suggests.
When James casually turned on the radio, only for Mariah’s hit Always Be My Baby to start, Mariah said: “That’s not an accident. I know your act.”
But that didn’t stop her from singing along with James, as they worked through tracks including Fantasy, Vision of Love and Thirsty.
When they weren’t singing James and Mariah showed off the different accents they can perform, with her revealing a hidden talent for speaking British.
But what we really loved is James’ expert knowledge of Mimi’s hits – he knew all the words, and she seemed to love that he obviously loved her.
They even indulged in some body rolling towards the end, which was amazing.
We dare you to watch this clip without smiling!