Justin Timberlake had the Eurovision audience on their feet as he performed his new song at the ceremony.
Mr SexyBack admitted he was battling a few nerves himself ahead of his big moment on stage.
Appearing in the green room to reveal what a fan of the competition he is and provide words of encouragement to the performers, he said: "We have been going all the way across Europe promoting our new film Trolls and then your people called my people and I said 'I've got to come to Eurovision'."
He told host Mans Zelmerlow, who won the competition last year with his song Heroes: "I saw the last two years and you are doing just as good a job as a host."
Addressing the performers, Justin added: "To all of you, I know what it's like to sing a song or perform a song for the first time, in front of how many people?
"I know you must have been nervous but you represented your countries so well and you must be so proud, cheers to you.
"I'm going to perform a new song tonight, I'm nervous myself!"
Justin took to the stage in a black blazer and jeans and a monochrome shirt and trainers to open his special guest performance with his hit Dance With Me before moving on to his new single Can't Stop The Feeling.
The audience in Stockholm were on their feet and waving flags from all over Europe as the star performed one of his signature high-energy dance routines in front of a brass section and backing singers.
After his performance, commentator Graham Norton said Justin will not be the last big American star to appear at the music competition "now they have realised this is the Super Bowl of Europe".