Details of the hen party are traditionally kept secret from the bride.
But with the added pressure of keeping the world guessing too, Pippa Middleton has gone to great lengths to keep the location of the do under wraps.
A source has revealed that Kate Middleton's sister has booked four venues in London for the night out.
Even the attendees are being kept in the dark.
"None of the girls know where they will be going - and won't until the actual day," the friend told the Daily Mail.
"Everything is being shrouded in secrecy."
Although the venues are not known, Kate is apparently keen on Eighty-Six, a trendy bar in Fulham and Public, a nightclub located in Chelsea.
Party planner Pippa is also reportedly organising a discreet, Dirty Dancing-themed bash at the Middleton family home in Buckleberry, Berkshire.