The 'Call My Name' singer famously fell out with Cowell after he replaced her with Nicole Scherzinger after just two weeks on the Fox series.
will.i.am told The Sun: "There are English guys that go to America and it's hard for them.
"Let's take Cheryl Cole for example - she went and did a TV show and it was hard for her. And it wasn't hard for her because of an American. It was hard for her because of a Brit.
"Now that's kind of weird, isn't it?"
Cowell had previously organised a birthday message for Cole's 29th birthday. A plane flew over the hotel in Las Vegas where the singer was staying with the message: "Cheryl - Congratulations you're 30 next year! ha ha ha Love Simon x."
Watch Cole's music video for 'Call My Name' below: