"There are some very surreal moments because, of course, as well as being Prime Minister, I'm a dad - I've got three young children," Cameron told British children's newspaper 'First News'.
"There are some moments when your responsibilities as a dad clash a bit with being a Prime Minister. I remember I had a son's birthday party once and when he blew the candles out on the cake, the fire alarm went off in Downing Street and I was stuck outside the building because the door went into lockdown, so there are some surreal moments," he said.
"I try to always remember that I am the Prime Minister and I can be called upon in a moment's notice to make an important decision, or talk to another prime minister or president, or take a decision about something that affects our country, so you're always on duty - so you can't let it get too surreal," he added.
The leader of the Conservative Party, who leads a coalition government along with the Liberal Democrats, also revealed that his least favourite aspect of his job was to face Prime Minister's Questions which take place on Wednesdays in the House of Commons.
Asked whether he was scared of the prospect of Labour leader Ed Miliband taking over his role after the May 7 general election, Cameron responded, "I think it would be a bad idea because I think I'd do a better job than him".