Jacinda Ardern has delighted a 12-year-old Metallica fan who petitioned to get the band to New Zealand when she paid him a surprise visit.

On Friday morning, the Prime Minister met with Hawke's Bay local William Bush to celebrate the news the metal legends will play one show in Auckland in October.

"I just wanted to come and say, on behalf of a lot fans in New Zealand, William, thank you for the effort that you put into bringing Metallica to New Zealand in October," Ms Ardern told Bush.

"I am reliably told that your petition actually made a real difference to Metallica and the promoters. I think it shows the power of a petition, so thank you for what you've done!"

"Yeah, it's quite awesome, great news to hear in the morning," Bush replied.

Last year, Bush launched a campaign to bring his favourite band to Aotearoa, with a Change.org page that received close to 7000 signatures.

"Dear Metallica," he wrote.

"Its been eight years since you've visited New Zealand shores and we are all hoping for your return!

"The bogans and metal heads of our country have had an eight year withdrawal and can't wait for the next time they'll get to see Metallica live in NZ.

"Who knows, Napier would be a great place for you to play! We believe this is long overdue and we deserve a Metallica concert!"

Bush's effort did not go unnoticed, even by Ms Ardern, who wrote the young music enthusiast a letter.

"It's great to hear about young New Zealanders who are passionate about music," she wrote.

"I grew up listening to Metallica and I'm really impressed by all the effort you have put into getting them to play a show in New Zealand.

"I hope you get to see Metallica play soon!"

Now, the 'Enter Sandman' rockers have made Bush's dream a reality, bringing their WorldWired Tour to Auckland's Mount Smart Stadium on Halloween night, October 31.

Ms Ardern presented Bush with two tickets to the show ahead of their sale to the general public on March 18.

The young fan said he'd probably take either his brother or his dad to gig, prompting the Prime Minister to joke, "that's a bit awkward, because I'm sitting right here!"

As to the decision of which family member would attend the concert with Bush, he conceded they may need to buy extra tickets when they went on sale.

"Well, as long as you buy them through legitimate means, we're of course trying to do something about scalpers," Ms Ardern said.

"Not Viagogo!" Bush added.

Bush finished the press conference with a rendition of Metallica's 'Seek And Destroy' on his electric guitar.

Newshub.