The clip, released Friday, features McGregor as an adult Christopher Robin who begins to rediscover his childhood after he is visited by Pooh in the real world.
After the pair find and gather the likes of Piglet, Eeyore, Tigger, Kanga, Roo, Rabbit and Owl, Robin returns home where he has lost sight of what is important in life including his family.
Pooh then decides its up to him and his friends to help Robin see the error in his ways after he has to miss out on a family vacation due to his job.
Christopher Robin, from director Marc Forster, is set to arrive in theaters on Aug. 3. Hayley Atwell and Mark Gatiss also star, along with Jim Cummings voicing Winnie the Pooh and Tigger, Brad Garrett as Eeyore, Toby Jones as Owl, Nick Mohammed as Piglet, Peter Capaldi as Rabbit, and Sophie Okonedo as Kanga.