SHANGHAI — Walt Disney Co. opened Shanghai Disneyland, its first theme park in mainland China, with a lavish celebration Thursday featuring Communist Party leaders, a children’s choir, Sleeping Beauty and other Disney characters.

A vice premier joined Disney CEO Bob Iger in cutting the grand opening’s red ribbon, showing the ruling party’s support for the $5.5 billion investment in promoting tourism at a time of slowing economic growth. They read letters of congratulations from the Chinese and American presidents, Xi Jinping and Barack Obama.

“This is one of the proudest and most exciting moments in the history of the Walt Disney Co.,” Iger said after the choir sang.

Later, actors dressed as Sleeping Beauty, Donald Duck and other Disney characters danced on stage.