The 50-year-old British actress - who shot to fame playing Daphne Moon in the US sitcom - has admitted she didn't even know what the axed 'x factor' judge does for a living.
She said: "People in the US haven't a clue who Cheryl is. I actually asked someone: 'Is she a pop star?'
"Yes, she is a huge star in the UK, but nobody knows her here."
The star added that she feels sorry for fellow Britons who try to find fame stateside, because she believes it is now harder to achieve than when she first cracked America.
She explained to the Daily Mirror newspaper: "I do have sympathy for English people coming over to America. I went over when I was young and stupid, but now English people come over when they are already successful in Britain.
"It is so much harder for them. They don't have the time to pursue things."