Delilah was released by Welsh singer Tom Jones in 1968 and became one of his signature hits. Over time Welsh rugby supporters adopted the chorus as an unofficial anthem, singing it at internationals in Cardiff long before kick off and after tries. Its call and response energy made it easy for large crowds to join, helping it spread through televised matches, fan videos and social media edits. Today the short clip is shared online as shorthand for Welsh rugby atmosphere and big stadium singalongs.