The 90-second clip shows Lin-Manuel Miranda, who plays London street lamplighter Jack, riding a bicycle as a storm approaches and the wind starts to blow leaves and a kite around town.
A little boy picks the kite up and Miranda's character helps him fly it.
As they look up at the sky, the clouds part and the figure of Mary Poppins -- played by Emily Blunt -- begins to magically descend.
She is later seen in a house, admiring herself in a mirror.
"Mary Poppins, it is wonderful to see you," says Michael Banks, played by Ben Whishaw.
"Yes, it is. Isn't it?" Mary replies.
The film is set for a Christmas release. It was directed by Rob Marshall from a screenplay by David Magee and screen story by Magee, Marshall and John DeLuca based upon The Mary Poppins Stories by P.L. Travers.
The sequel to 1964's Mary Poppins features Blunt "as the practically-perfect nanny with unique magical skills who can turn any task into an unforgettable, fantastic adventure."