Simu Liu's 32nd birthday was a particularly memorable one as the actor tells PEOPLE
Simu Liu
Credit: Albert L. Ortega/Getty

The first trailer for Shang-Chi and the Legend of the Ten Rings was a "very special" surprise for its leading man Simu Liu.

Liu, 32, spoke to PEOPLE about what it felt like to see the trailer for the Marvel film on his birthday while promoting his partnership with the California Milk Processor Board, the creators of 'got milk?.' Together they're announcing a new alliance with No Kid Hungry to provide up to 1 million meals to kids in need throughout California. 

"It came out on my birthday, and nobody told me that it was coming out on my birthday so I was a little under-prepared," Liu tells PEOPLE of the trailer's debut in April. "A couple of days before my birthday, Marvel contacts me and they're like, 'Okay, well, we want to debut the teaser poster. So will you help us do that?' I was like, 'No problem.' I thought, 'This is such a wonderful birthday gift. I'm down.'"

On the morning of April 19, Marvel Studios surprised Liu with the first trailer for the film.

Simu Liu
Credit: Rachel Murray Framingheddu for CMPB/Getty

"It was a pretty incredible moment," Liu says. "I'm sure that they don't do that for everyone, so I felt very special. It was really, really cool."

The character of Shang-Chi first appeared in Marvel comics in 1973. He was trained as a martial arts assassin by his father, the villain Fu Manchu, but rebelled against his father's lessons and became a hero.

The response to the trailer was "nuts," he continues. "People were really excited, and I think there's a real hunger for more diverse stories to be told. It's particularly in the space of superheroes and all that. I really do think it's about time, and I can't wait for September 3rd to come." 

Joining the Marvel Cinematic Universe has opened a multitude of doors for Liu, but "helping kids and uplifting children has been one of the things that I've been looking forward to the most since stepping into this role in the MCU," he says. 

Along with his California Milk Processor Board and No Kid Hungry partnerships, Liu launched the campaign challenge #StayStrongTogether, which is dedicated to celebrating strength, resilience and the adaptability of the human spirit — all attributes that reflect Shang-Chi. 

Simu Liu
Credit: Rachel Murray Framingheddu for CMPB/Getty

"We've all heard that speech from Uncle Ben in Spider-Man, 'With great power comes great responsibility,'" says Liu. "I remember what that meant for me as a kid to hear those words being spoken, and it's something that I carry with me to this day. Being in a position like I am now, I feel very fortunate that I'm here, but I want to be able to help as many people as I can."

Never miss a story — sign up for PEOPLE's free weekly newsletter to get the biggest news of the week delivered to your inbox every Friday.

Shang-Chi and the Legend of the Ten Rings
Simu Liu
| Credit: Marvel Studios

As part of his partnership with 'got milk?', Simu kicked off the first #StayStrongTogether social share-out with the debut of a fun video he collaborated on with 'got milk?' and Wong Fu Productions. The video showcases ways in which Simu harnesses his own positive "Stay Strong" mindset.

Liu has encouraged fans to share their own posts with #StayStrongTogether on social media. Beginning Thursday through June 30, each #StayStrongTogether post shared and engaged with on Instagram and Twitter that mentions @gotmilk and tags two friends to join the movement raises a $1 donation for the No Kid Hungry campaign to help contribute meals towards the 1 million meals goal. 

"My favorite part of this campaign is really it hammers home the idea that we are one community and we will go up or down together," Liu says. "It's our hope that we'll continue to uplift each other and to be there for each other."

Shang-Chi and The Legend of The Ten Rings hits theaters on September 3.