Mia Hamm 'Heartbroken' Over Grant Wahl's Death: 'Our Game Was Better Because Grant Wahl Was in It'

Getty (2) Mia HAmm and Grant Wahl

Mia Hamm is mourning her friend, the journalist and women's soccer advocate Grant Wahl.

The famed sports journalist was covering the FIFA World Cup in Qatar when he collapsed Friday. His cause of death remains unknown.

"I was shocked," the two-time World Cup champion says in an exclusive interview with PEOPLE. "I remember seeing it on Twitter and I think I had to reread it three times. I was in shock and heartbroken for his wife and his family."

Hamm shares that Wahl was an early supporter and advocate of the women's game. "I remember seeing him around with National Team games. I remember seeing him in our first domestic league, the WUSA final. He was just a huge advocate for the players and our game."

RELATED:  Journalist Grant Wahl, Who Was Detained for Wearing Gay Pride Shirt at the World Cup, Dead at 48

The soccer star, who spoke as part of her partnership with Frito-Lay during the World Cup, continues: "He was very outspoken in helping us get to where the game is today. And couldn't be more grateful for his voice and his support."

"Grant loved this game," Hamm says. "And he loved talking about it. And he loved sharing the stories. And just our game is better because Grant Wahl was in it."

Grant Wahl

In 1998, Wahl pitched a story to his editors at Sports Illustrated about a young female soccer player named Mia Hamm, according to The Washington Post. That story helped kickstart his career covering soccer.

RELATED: Everything to Know About the 2022 World Cup and the Controversy Over Host Country Qatar

Wahl covered soccer and college basketball for decades at Sports Illustrated before leaving to run his own website. Back in 2002, he wrote about a then-largely unknown high school phenom, LeBron James, for a cover story called "The Chosen One."

Never miss a story — sign up for PEOPLE's free daily newsletter to stay up-to-date on the best of what PEOPLE has to offer, from juicy celebrity news to compelling human interest stories.

James was asked about Wahl soon after his death on Friday, and the NBA star started by saying, "my condolences go out to his family."

"I'm very fond of Grant and having that cover shoot; me being a teenager and him covering that, it was a pretty cool thing," he recounted. "And he was always pretty cool to be around. He spent a lot of time in my hometown of Akron, covering me over the course of time before that cover story came out."

"... It's a tragic loss. It's unfortunate to lose someone as great as he was. I wish his family the best and may he rest in paradise," said James.