Brown signed a five-year, $304 million supermax extension with the Celtics in July.

Jayson Tatum expressed happiness for Jaylen Brown as his co-star received a supermax extension. (Jim Davis/Globe Staff)

Jayson Tatum is not only happy to see that Jaylen Brown is staying with the Celtics for a long time to come, but he’s also excited that his co-star was able to receive a supermax deal.

Speaking to The Boston Globe’s Gary Washburn at the Basketball Hall of Fame enshrinement ceremony on Saturday, Tatum publicly commented on Brown’s extension for the time since he signed it in late July.

“Much deserved, it was a no-brainer,” Tatum told Washburn. “So I’m happy for him and his family. It’s life-changing. It’s a big deal. I’m happy we’re going to have him for however much longer we’ve got him for. I’m happy about that.”

The deal Brown signed was a five-year, $304 million extension that will keep him under contract through the 2028-29 season. Ideally, for the Celtics, it’ll help keep him and Tatum together through almost the end of the decade.

Tatum is actually eligible for a contract extension next offseason. And because he made an All-NBA team for the second straight season, Tatum can earn a supermax deal as well.

It was projected that Tatum’s supermax extension would be worth $318 million over five years in May. But it could be higher than that as Brown’s deal ended up being $9 million richer than what it was originally projected when both stars were named to an All-NBA team for their performances this past season.

However, Tatum doesn’t seem to be too focused on how much money he can earn next summer.

“Nah, I don’t think about nothing of that,” Tatum told Washburn. “It’s one day at a time.”

Tatum is still under contract through at least the 2024-25 season and holds a player option for the 2025-26 season. So, he should be in Boston for the foreseeable future.

As for why Tatum was at the Basketball Hall of Fame ceremony on Saturday, he said that he was there to support Dwyane Wade. The Miami Heat legend was one of the 10 people officially enshrined on Saturday. Wade actually praised Tatum in an interview with Sports Illustrated recently, saying Tatum is “one of my favorite players in the NBA, he’s one of my favorite people in the NBA to communicate with.”

While Tatum is friendly with Wade and Heat star Bam Adebayo, it appears Celtics fans don’t have to worry about him taking his talents to South Beach. When a Heat fan told Tatum to “come to the Heat” during the red carpet event ahead of Saturday’s ceremony, the Celtics promptly replied “nah” with a smile as he continued walking.

Tatum and the Celtics will look to avenge their Eastern Conference finals loss to the Heat this upcoming season, which Tatum told Washburn he’s “excited” to get going but is also “going to enjoy my summer a little bit” before training camp opens in September.