Tina Fey worries that her career won't last forever.
The actress-and-screenwriter is aware of the cut-throat nature of showbusiness and fears she could have the same fate as other stars whose careers are now "over".
She said: "You cannot count on showbusiness to be interested in you forever and ever. I have a friend, a veteran agent in Los Angeles. She says, 'He's cold. He's cold,' about some actor or other. And it's over for them. That could happen to me."
Although Tina - who is expecting her second child with her husband Jeff Richmond, with whom she already has a five-year-old daughter Alice - knows how fickle the industry is, she has loved it from the beginning, despite acknowledging its negative aspects.
She said: "Yes, there was bad pay, there were tough gigs and there were cr*ppy hotel rooms with bits of blood on the toilet seat. But at the time it was always the greatest thing ever. I was just excited to be in showbusiness."
However the 40-year-old funnywoman admits she feels the pressure of balancing her work with her personal life and is thankful that she has had the chance to do everything she dreamed of already.
She explained to Sunday Times magazine: "The thing I feel up against is the balance of family and work.
"In some ways, the things I wanted to do, I have done. I got to be in a movie, I had a TV show for a minute..."