Apple is promoting Earth Day this Saturday with the latest Apple Watch Activity Challenge. The new Earth Day Challenge encourages Apple Watch users to go outside and complete a 30 minute outdoor exercise to unlock new iMessage stickers and a special achievement award. Check out the stickers below:

The new Activity Challenge for Apple Watch users is already popping up for customers in the eastern hemisphere and should arrive overnight for users in the United States.

Get outside and celebrate Earth Day on April 22 and earn this award. Go for a walk, run, cycle, wheelchair or swim workout of 30 minutes or more in the Workout app or any third-party app that writes these workouts to Health. You will also earn special stickers for Messages.

Apple has previously promoted Activity Challenges with both Thanksgiving in the United States and New Year’s Day around the world with specific workout challenges.

These are the stickers that will be unlocked when completing the new Earth Day Challenge:

Apple is also highlighting Earth Day with a special Apple Store event in San Francisco tonight hosted by Apple’s Lisa Jackson and former U.S. Vice President Al Gore.

Thanks Ben!