Matt Damon smiles for a teenager's screaming fans at New York Comic Con

It's Matt Damon's birthday.

As a crowd of thousands sings to him at Madison Square Garden for New York Comic Con and Damon still rides the high of reprising his role as Will Hunting the night before, the elephant in the room is that he isn't the biggest star here.

When ear-splitting shrieks cut through the air at MSG, it's for Junkai Wang, the 17-year-old singer who makes his film debut alongside Damon in the The Great Wall.

If The Great Wall casting Jason Bourne alongside China's Zayn Malik seems like a bizarre creative decision, know that it's representative of director Yimou Zhang's vision.

"This movie is made for the world audience," Zhang said via translator at the panel.

The film took three years to complete and stars Damon and Pedro Pascal (Game of Thrones, Narcos) as foreign soldiers who stumble into an ancient war bigger than anything they could've imagined -- a war waged along the Great Wall.

"Ultimately it's a monster movie," said Damon, referring to the mysterious mythical creatures glimpsed in the trailer (below). "Monsters are attacking the Great Wall and we all defend it."

Damon and Pascal were both massive fans of Zhang's work before reading The Great Wall. Pascal wanted to work with the director ever since seeing Hero. Yimou has directed almost 30 films, and also helmed a cute little variety hour known as the Beijing Olympics Opening Ceremony.

The female lead is Chinese actress Jing Tian, who describes her character as "strong, brave, determined" and "incredibly powerful" as a leader in the army.

"One of the things that I love most about the story is the equality between men and women in leadership roles," Tian said to wild applause at the panel. "The respect that all these characters have for one another regardless of gender is something that I wish we could see more in films, and in real life for that matter."

Wang's fans fill the front rows at Madison Square Garden, standing and jumping for his arrival and holding up handmade signs (these stay up, as do the phones on which they photograph and record as much of his speech as possible). Damon laughs when the moderator says he isn't the biggest name in the movie. "I'm not even close," the actor laughs.

But he's an integral part of what Damon himself describes as a "spectacular international cast," which also includes Willem Dafoe, Andy Lau, Numan Acar, Najid and Eddie Peng. Wang's name isn't even in the trailer, but it doesn't look like that will in any way deter his fans from coming out in droves.

Halfway through the panel, Damon gets a birthday text from his father.

"Happy birthday, my boy," Damon read to the crowd. "My birthday present to you is letting you know that in exactly one month we can kiss Trump goodbye."

That'll be one less wall to worry about.