Why Lorde is back in Auckland

Pop star Lorde couldn't make it to the Met Gala in New York this year - but she's made it to her big sister's graduation in Auckland.

The singer earlier this week announced she was heartbroken to have to missed the annual fashion event - where she turned heads by wearing a cast in 2016 - and had been performing at the New Orleans Jazz Festival.

But her mum, poet Sonja Yelich, on Wednesday night posted a video of the Grammy- award-winning singer lifting up older sister Jerry Yelich-O'Connor - in graduation robes - in front of Albert Park's fountain.

"Sooooo proud! [Jerry] graduated today from the University of Auckland with a [Bachelor of Commerce and Bachelor of Arts] conjoint," Yelich posted on Instagram.

"Me n [Lorde] flew back from the US just for this day[sic]."

Yelich - who was with her daughter in the US - tweeted they had arrived back in Auckland on Wednesday.

- AAP