Molly Smitten-Downes from Rothley in Leicestershire could sing before an audience of 120 million people during the Eurovision Song Contest in May.
She is a relatively unknown artist compared to some previous performers: last year Bonnie Tyler came 19th and Engelbert Humperdinck was 25th out of 26 acts in 2012.
Molly said: "I'm so excited for everyone to hear Children of The Universe. I'm so happy with it.
To represent the United Kingdom in such a huge competition, not only as a singer and performer but as a songwriter is an unbelievable honour. I hope I can do us proud."
More top news
Up to 90,000 Aston Villa, Shrewsbury Town and Coventry City fans are expected to descend on the capital over the bank holiday weekend.
Peterborough United have continued their busy start to the summer with the signing of Dundee midfielder Mark O'Hara.
Mekel Sterling was mistakenly shot dead outside shops in Birmingham in September 2017.