The legendary US radio host has launched an astonishing verbal attack on the British singer, predicting his career success will be short-lived.
Stern, who is also a judge on 'America's Got Talent', said: ''Do you know what I love about that guy? He's an ugly motherf****r.
''He's fat. And I love it. You know what, he looks gay to me. Not that anybody looks gay but he does seem effeminate.''
What's more, Stern predicted the singer will be a one-hit wonder with 'Stay With Me', even though he already has a string of other successes.
He said: ''I feel like that will be his only hit song.
''I'd like to get him in here and congratulate him on beating the odds.''
Meanwhile, Sam recently confirmed he'd split from his boyfriend Jonathan Zeizel.
The pair met on the set of Sam's video for 'Like I Can', but have decided to call it quits after two months of dating.
However, Sam remains hopeful of finding love again ''soon''.
He said: ''Hopefully I will find someone soon and when I do I think it will be a bit more difficult to sing songs because I will want to sing happy songs. Right now when I'm on stage I feel like it is good for me, it is like therapy every night.
''The music comforts me.''
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