The five-year-old melted hearts as she was spotted gazing adoringly at her mum and clapping as the singer accepted the award for best urban contemporary album.
Corden stepped into a giant cardboard cutout of a compact car as he gathered Jennifer Lopez, Tim McGraw, Faith Hill, Keith Urban, John Legend, Ryan Tedder, Jason Derulo and Neil Diamond for a chorus of Diamond's 'Sweet Caroline.'
The bit was clearly planned, but about halfway through, little Blue ran up to join the group in a moment that seemed genuinely impromptu.
The youngster was sitting in the front row of the arena and had just finished watching her expectant mother's show-stopping performance of two selections from 'Lemonade,' complete with an elaborate hologram introduction.
Blue, who turned five on January 7, also paid an adorable tribute to Prince, wearing a pink tuxedo with white ruffle blouse.