Booking shore excursions with Celebrity

I want to book several shore excursions in advance for my South American cruise in December. I was told by an agent at Celebrity that as soon as you book the excursion your credit card is charged. Is this true? On other cruise lines you are not charged for the excursion until you are onboard and the charge goes onto your shipboard account.

Your credit card will be billed. This is the same on HAL