Tina Fey felt like a failure when couldn't breastfeed her baby.

When the '30 Rock' actress gave birth to her daughter Alice in September 2005 she wanted to nurse her but couldn't produce enough milk naturally and admits she found the experience tough.

Tina - who is pregnant with her second child with husband Jeff Richmond - described how she would watch episodes of TV show 'Entourage' while trying to extract milk with a breast-pump and felt guilty when she was forced to feed her baby formula instead.

She said: "I chose to pump every two hours while watching the HBO series 'Entourage'. I was able to do this for seven weeks before running out of episodes and sinking into a deep depression.

"However, the baby was thriving. I was no longer feeling trapped, spending 30 out of every 90 minutes attached to a Williams-Sonoma T*t Juicer. But I still had an overwhelming feeling of disappointment. I had failed at something that was supposed to be natural."

The 40-year-old comedian also found it difficult being around friends who had managed to breastfeed their children successfully and she would constantly compare herself to other new mothers.

Writing in her comedic memoirs 'Bossypants', she revealed: "I was defensive and grouchy whenever the topic came up. At a party where a friend was successfully nursing her little boy, I watched her husband produce a bottle of breast milk the size of a Big Gulp. It was more milk than I had produced in my whole seven weeks - I blame 'Entourage'."