Guest Stars is a side event that where you can play randomly selected levels and collect Stars with special Guest Birds to earn rewards and permanently level-up each of the Guest Birds in your collection! You can access Guest Stars screen from the “Fun Stuff” menu or from pressing the button at the bottom of the map screen.
You can pay Gems or watch an advert, when available, to play a level in the Guest Stars screen. If you beat the level, all stars you earned will be added to the track and you will earn rewards when reaching the targets shown on the screen. All Stars you collect with each Guest Bird will also fill the level meter for that bird. When a Guest Bird levels-up it gets a higher style multiplier, forever! Level-up your whole collection by coming back each day and completing the special levels.
If you want to check your progress on levelling-up each of the Guest Birds, or see when your favourite Guest Bird will return, you can check the schedule by pressing the calendar button. Most Guest Birds always return on the same day each week, but some Guest Birds only come back on alternate weekends.
Guest Birds can be used in the main level progression too. You can use your levelled-up birds and their special abilities to get extra style points to help you advance faster in the current season (see: What are Seasons).
The Guest Stars feature is only available when playing online.