Ariana Grande has joked she hid in the bathroom when Big Sean sang to her at a restaurant.

The 21-year-old star has confessed she found herself getting embarrassed when the 26-year-old rapper decided to stand up on a chair during a date and serenade her with Stevie Wonder's classic song 'Isn't She Lovely'.

Sharing a black and white photo of her and her boyfriend of several months on Instagram, she wrote: ''fyi he stood up on his chair & started singing Stevie Wonder at the top of his lungs after this photo was taken and i ran to the bathroom and hid (not actually) (sic).''

Meanwhile, Big Sean - who features on his girlfriend and Iggy Azalea's hit single 'Problem' - is said to have been sending Ariana videos of himself singing so she doesn't miss him too much when they're away from one another.

A source said previously: ''When he's away, he check in with her all the time, which really helps.

''A few days ago, he made a little video of him singing to her in an elevator. She loves that kind of thing. She just wants to know that even when they aren't together he's thinking of her.''