This is about Radio-host/DJ, Palle Peter Jencel, who was DJ at Frederik's 50th birthday party that took place at Kancellihuset (assuredly) at Fredensborg.
He tells a few details in a podcast.
It was a surprise-party arranged by Mary, with the theme: Festival.
He was placed in a room (with his equipment presumably) in a living room and BTW when he had to go to the bathroom, he had to walk through M&F's private bedroom. (Which is why I'm sure it was in Kancellihuset, and I know from other sources at the time, that there was a party at Kancellihuset.)
He was hired to play from 15-04 and as always he got quite a few requests from the guests present.
Not least the royal children:
"All they wanted to hear is Gilli and Kesi, and you really can't stand there playing that for 200 affluent people in nice clothes.
They are standing there, doing that floss-dance that young people dance today."
And the requests continued, one from Mary:
"I know it sounds a little odd, but can I request a song?
Do you have Rage Against the Machine with Killing in the Name?"
(See the music video in the article.)
Another request came from Mary's sister, who was pretty delighted with Lars Ulrich from Metallica being among the guests. And she simply insisted that he played something by Metallica.
Even though most of the requests was rock music, he did put on Macarena at some point:
"Then the whole crowd begin to dance Macarena."
At 04.30 a tired Mary decided the party was over and Palle Peter Jencel hitched a ride with M&F and Mary's sisters to Copenhagen:
"We drive into Amalienborg Square, the sun is up and we say thank you for a nice evening. I get out and it's only there it dawns on me, what has happened."
Apart from Palle Peter Jencel being a DJ, the bands Gulddreng and Nephew also played during the party.
Here is Gilli & Kesi, who I must confess I didn't know.
But metallica I do know!
But in the evening the children were put in bed and the party moved inside:
"Everybody danced and they have this cardboard cutout of Frederik that is being crowd-surfed around."