The 'Stay With Me' singer is a massive pop culture fan and was overawed when he met the brunette beauty because he is so obsessed with her reality show 'Keeping up with the Kardashians'.
Sam, 22, told The Sun newspaper: ''I s**t my pants when I met Kim Kardashian because I've been watching their whole series.
''She probably wears a lot of make-up but she looks like she doesn't, she was natural.''
And Sam was particularly excited when Kim - who has 14-month-old daughter North with husband Kanye West - told him her whole family were fans of his.
He added: ''The first thing she said was, 'I just texted Kanye and told him you're here'.
''She told me their whole family has been listening to my record. Kendall Jenner loves it and they play it all the time.''
The singer has just been asked to perform at the MTV Video Music Awards, which means he'll get to appear in front of his idol Beyonce and he is already worried about getting starstruck.
Sam reflected: ''I don't know how I'm going to hold it together.
''If I sing and she's in front of me, I'll just cry. My music is so heavily inspired by her.''