Los Angeles
The 52-year-old star has a seven-year-old son and a four-year-old son with his wife Quinn Lundberg.
He told 'Entertainment Tonight': "My kids think I'm a librarian somewhere. They don't even know. They think I'm an assistant librarian somewhere."
The 'Between Two Ferns' star also joked that his boys "shall never know" of his 2009 hit movie 'The Hangover', reports femalefirst.co.uk.
He quipped: "I'll just deny it. I'll say, 'I don't know what you're talking about. I had nothing to do with that movie'."
The comedian says the subject of his fame remains "tricky".
He continued: "You wanna protect their innocence as much as possible. They're just children. People used to come up to me and be like, 'Oh, my kids love 'The Hangover', and I'm like, 'You're a terrible parent'. They need to mature a little bit before they see that."
Meanwhile, Zach previously claimed that he owes much of his success to the internet. He doubts he would've become so famous in a pre-internet era.
Asked whether Hollywood has changed at all in terms of prioritising looks, Zach replied: "Without the advent of the internet, I would be an out-of-work actor. It would still be three networks on television.
"I remember auditioning for 'Frasier' and the casting director called my manager; I was told to 'take a bath' next time I come. That was the feedback."
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