Speaking to Digital Spy at the Philips British Academy Television Awards, Hart explained that it takes a long time to put the show together.
"[It's] mainly because I has got to write it," she joked.
"We only finished the second series at the end of December... It just takes that while to come up with ideas, have a little bit of a break and see the world to get inspiration."
Hart also revealed that she only began thinking about the new episodes "a couple of weeks ago" and joked that if she did have any ideas it would be "classified information".
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> BAFTA TV Awards 2011: Red carpet pictures
> BAFTA TV Awards 2011: The winners in pictures
> Read our full coverage of the BAFTAs
Watch our red carpet chat with Miranda Hart below: