Optimus Prime & Bumblebee will be at the Changi Airport Terminal 3 on 6 & 7 August (i.e. tomorrow and Sunday)! Heh, for those Transformers fans who want to have a photo grab with these autobots, make your way down to the Changi Airport T3 these two days at 1 pm and 4pm. I am not sure how the photos will turn out since it is quite hard to make 'Transformers' mascots, but I am sure the fans will still be thrilled nonetheless. The event will be at Basement 2, just opposite the kopitiam area.
Changi Airport has these Meet & Greet events (I saw the Kung Fu panda event sometime back), which are also publised on their website. However, the details on the website are a bit different from the terms and conditions posted at the event itself. The website stated that interested parties can just spend "any amount on a single receipt" but the T&Cs at T3 stated a minimum amount of $10 ($5 for Changi Reward members) before a person can qualify for the photo passes.
Thus to be safe, interested folks should ask the Changi Airport staff before they start to hand out the Transformers photo passes. Here's the picture of the T&Cs.