Sam Smith says his song 'Lay Me Down' changed his life.

The 23-year-old singer took to Twitter to start the hashtag ''HappyBirthdayITLH'' to mark the mark the one-year anniversary of his chart-topping album 'In The Lonely Hour' and admitted that song is the track he is most proud of from the LP and teaches him new ''lessons'' all the time.

In a series of tweets, he revealed: ''Lay Me Down - we end where we began. #HappyBirthdayITLH ... This was the first song I wrote for this record and the first song I ever wrote with my writing partner @jimmynapes ... This song changed my life and sent me in the direction where it was all about the voice ... F**k looking a certain way, or singing a certain 'sound' it's about the soul, the voice, and the passion, and the truth ... Lay Me Down continues to teach me lessons every day... (sic)''

Sam also opened his heart about the song 'Not In That Way' which he claims always hits him in ''the gut'' because the lyrics deal with his unrequited love for the man who inspired the record in the most honest way.

The singer/songwriter - who is currently recovering from corrective voice surgery - revealed in more posts: ''Not In That Way - now we get deep ... All my life I've been looking for a song that hits me in the gut & makes me feel how unrequited love makes me feel. This(for me)is that song ... It explains perfectly how you can love someone with all your heart, but just not in that way. That's powerful and real to me. (sic)''