However, things started to go wrong immediately. An animated pizza introduced him, walked on stage, and sat at a desk that looked similar to the one in his video for the song.

Within seconds, it was obvious something was wrong as he started pretending to tap at a computer keyboard, and you could hear isolated random vocals but no music.

Confused, he said: "What's going on. We've got sound problems." One of the presenters for the evening, drag race star Tia Kofi, returned to the stage and asked the audience for an "awwww" before turning to Sam. "I'm not going to lie - that is what happens when you are such a creative inventor that you put together little organs made of Furbys," she quipped.

Jokingly, he said, "I forgot to press play one sec. Or maybe it's the wrong user name." He played with the fake computer on stage for a while before the opening animation appeared on screen again, announcing his entry.

Lest the audience thought this was part of the act, he announced: "This wasn't meant to happen by the way. But it's OK. We're all in it together." The track then started playing, and he was able to finally perform it live.

It was the second time that night he had his thunder stolen, as hours before he took to the stage, the Luxembourg entry Eva Marija had performed a stripped-back version of his song to a rousing reaction. The 20-year-old has been studying in London for the past two years and wanted to show her appreciation for her adopted country.

Prior to performing, Sam had exclusively admitted to Express.co.uk that the magnitude of the night had only just struck him.

"This is the first time performing it live. I hadn't really thought about it till people were telling me that it is, but it's kind of making me a little bit nervous [now], really," he laughed.