Holiday Song (it's not what you think)

Alright. So about 15 years ago one of my friends at the time had me watch a music video that was absolutely ridiculous but the song was catchy AF. It was definitely a pop song and all I can remember of the lyrics is " a holiday, a holiday". It was 2 possibly British dudes singing, in one shot of the video there was a white horse (possibly a unicorn) galloping with a dark background, a diamond exploding and these two lanky dudes. I have spent so many hours of my life trying to remember more of the words and have searched high and low for years. Help me reddit! You're my only hope!