Sam Smith reveals what he wrote to Lady Gaga to make her cry

Sam Smith has opened up on the email he sent to Lady Gaga.

The US star recently took to Twitter to admit that she was left in tears after reading a message from the Brit.

She said at the time: "You're so special my baby. Your email made me cry @samsmithworld With the voice of an angel, u need no permission or advice. You're perfect."

The 'Stay With Me' star has now told Boston's 103.3 AMP Radio that he wrote to her about how her rise to fame inspired him.

Smith said: "I wrote her an email basically just saying, 'I remember being a 17-year-old, queuing up for your concert, dreaming up doing this, and being in the music industry'.

"And the thing I admire the most about Lady Gaga was the hustle and what she did to get into the industry. And I just ran with it saying, 'Thank you for inspiring me to do this because the reason why I'm here now is partly because of you'."

Watch Sam Smith perform live below: