Read a review of Lorde's concert last night at Silo Park: Lorde live: Glowsticks, f-bombs and two new covers
About two hours later, a tweet from the Splore music festival account revealed the singer had been sick before the show.
LORDE was late on stage because she was vomiting. What a pro! #fact
The nearly sellout crowd was none-the-wiser, with her show receiving rave reviews.
Mr MacLachlan did not go into detail about what was wrong with Lorde, simply saying she had been unwell.
"These things happen and she's had a busy three or four days, and also just got off a flight.
"She's definitely feeling better. It was an incredible crowd and and incredible show because it had a real homecoming feel so I think she thoroughly enjoyed it,'' he said.
Meanwhile, Lorde's Twitter rant slamming New Zealand media for being pushy at Auckland Airport has made headlines overseas.
A series of tweets from the singer - which were quickly removed - have been published by British music magazine NME and entertainment website E online.
"nz media almost pushed over myself and my family at the airport this morning in order to get their shots. bit of a sad welcome if i'm honest,'' one of the tweets read.
"i understand that people of note are supposedly fair game for everyone to photograph and film but that doesn't make it acceptable.
"i'm beginning to get used to my image as a public commodity, and the fact that I'm getting used to it frightens me,'' she said on the social media site.
READ MORE: Charlotte Dawson tells Lorde: 'Leave NZ'