The Scottish DJ - who has been dating Taylor since February of this year - performed with just ''an acoustic guitar'' about how the 'Bad Blood' singer is ''rare in their world'' and that it was ''love at first sight'' and while serenading her, he complimented her feet.
A source revealed: ''It was really romantic, just him and an acoustic guitar, about how she's so rare in their world, love at first sight. there's a funny line in there about how even her toes are perfect!'
The 25-year-old superstar is believed to have ''laughed so hard because she thinks they're her worst feature and he think's ''she's crazy''.
A source told America's OK! Magazine: ''She laughed so hard because she thinks they're her worst feature and he thinks she's crazy.''
The blonde beauty is said to be ''very much in love'' with Calvin and is ''convinced she's finally found Mr. Right'', according the source.
The source added: '''They're very much in love and she's convinced she's finally found Mr. Right.''