Taylor Swift's father has warned her boyfriend Harry Styles not to break his daughter's heart.

Scott Kingsley Swift wants the couple to ''slow down'' because he is concerned about the 23-year-old beauty - who has had failed relationships with a string of big stars including Jake Gyllenhaal, Joe Jonas and John Mayer - being left ''devastated'' if the pair split.

A source told The Sun on Sunday newspaper: ''He likes Harry but he wants them to slow down and take things easy. It's clear to everyone they are smitten with one another and already talking about marriage.

''He doesn't want them to split up as fast as they've got together and for Taylor to end up devastated.''

But Taylor - who is very close to her parents and wrote the song 'The Last Day', from her second album 'Fearless', about them - and Harry have shown no signs of cooling down after the One Direction singer hired a yacht to take them to two private islands during their romantic break in the Caribbean.

A source told the Daily Star Sunday newspaper: ''Harry and Taylor kept getting hassled for pictures by fans on the island so he hired a yacht for two days and one night to take them to two private islands.

''He organised snorkelling and a chef to cook gourmet meals when they wanted.''