Beyonce was joined on stage during her opening performance at the 94th Academy Awards by a slightly younger back-up dancer, her daughter, Blue Ivy Carter.

The 10-year-old took front and centre next to her award-winning mother as she sang Be Alive, for which the star is nominated for best original song.

The tune features in the biopic of Richard Williams, father of tennis stars Venus and Serena Williams, and stars Will Smith in the leading role.

Introduced by the Williams sisters, Beyonce wore a lime green dress and matching gloves as Blue Ivy, sporting a fun pair of sunglasses, merged with the group of dancers also wearing tennis ball green.

She knew the choreography as she moved to dance in front of her mother, who stood on a podium behind.

Her mother, singing from a tennis court in Compton and surrounded by a choir and orchestra, finished the performance with a salute.

The musician shares Blue Ivy with rapper Jay-Z, who she married in 2008.

The two also have twins Rumi and Sir.