Babies -- especially royal ones -- have their own agendas.

Yes, Kate Middleton and Prince William's little one is officially scheduled to make his or her grand entrance on July 13 . . . but that doesn't mean he or she won't pull a North West.

PHOTOS: Kate Middleton's royal pregnancy style

Here's where you come in: We're asking Us Weekly readers to put their guestimation skills to the ultimate test. Predict the future monarch's birth date and weight, get them right, and you could score a 7-day Caribbean vacation on Princess Cruises' Royal Princess, christened by Kate.

PHOTOS: Kate Middleton's motherhood prep

Think you're up to the task? Click here to submit your best guesses.

PHOTOS: Kate's childhood album

* NO PURCHASE NECESSARY. Void where prohibited. Open to residents of the United States and Washington, D.C. (EXCLUDING RESIDENTS OF OVERSEAS MILITARY ­INSTALLATIONS, PUERTO RICO AND OTHER U.S. TERRITORIES), who are 18 years of age or older as of 6/26/2013. To enter, log on to and follow the registration and entering directions. Grand prize winners: 1; ARV: $2,388. Runner-up winners: 20; ARV: $69.95. Odds of winning depend on the number of eligible entries received. Sweepstakes begins at 9:00 a.m. edt on 6/26/2013 and ends on 11:59:59 p.m. edt on 7/3/2013. Certain restrictions may apply. Complete Official Rules are available at

This article originally appeared on Kate Middleton Baby: Guess the Royal Baby's Weight, Birth Date and Win a Cruise!