LeBron James will turn 40 in December. Stephen Curry is 36. Kevin Durant will turn 36 and Jimmy Butler will turn 35 by the time training camps start in the fall.

They have been stars of the playoffs for years, players who come up biggest at the biggest times.

But not this year. The next wave isn’t waiting its turn anymore. They’re here — a bunch of 20 somethings, with one of them set to be the best player on the team that will be crowned the best in the NBA about a month from now.

It’ll be either Boston, Dallas, Indiana or Minnesota as the last team standing when the NBA Finals end next month. The best players on those teams — Jayson Tatum and Jaylen Brown for the Celtics, Luka Doncic for the Mavericks, Tyrese Haliburton for the Pacers and Anthony Edwards for the Timberwolves — are all in their 20s.

Brown is 27. Tatum is 26. Doncic is 25. Haliburton is 24. Edwards is only 22. James, Curry, Durant and Butler are still considered greats, but some of the NBA’s star torches sure seem like they’ve already been passed down to the next generation.

“They have no fear,” Dallas guard Kyrie Irving said of the young stars. “They don’t see the O.G. superstars as guys that they look up to as much anymore. They want to kill our records. They want to kill us every time they get on the court. That was the first thing I noticed about Luka, that he just had no fear going against the best in the world. He always walks around like he’s the best player in the world. I think that’s the confidence of a champion. That’s where it starts.”

Out of the 21 regular starters used in the playoffs by the four teams left, only six have turned 30: Boston has 37-year-old Al Horford and 33-year-old Jrue Holiday, the Mavericks have the 32-year-old Irving, the Timberwolves have 36-year-old Mike Conley and 31-year-old Rudy Gobert, and the Pacers have 30-year-old Pascal Siakam.

“Thanks for calling me old,” Siakam said to Haliburton on Sunday, after Haliburton tried explaining how the Pacers have a bunch of players who are basically new to this stage and one in Siakam who has a championship from his time in Toronto.

To be fair, in these playoffs, 30 might seem old.

“It’s high-stakes games and it’s going to be crazier as we go,” Siakam said of playing at this time of year. “But I think as long as we stay together, we have a great group of guys … I think that we can lean on each other. They can lean on me for experience, I can lean on them just continuing to learn how to play with them. We’ve just got to go out there and play and believe that it’s possible.”

Experience, right now, surely favors Boston.

The Celtics have five players (Brown, Tatum, Horford, Holiday and Derrick White) with more than 200 career points in the conference finals and the NBA Finals; the other three teams still in these playoffs have two such players, combined (Irving and Siakam).

“It feels like it’s been a long time coming, just being back in this position, getting back to the finals or the conference finals,” Irving said. “It’s just a long way back.”

Irving is truly a rarity in this NBA final four: He has a ring, won with Cleveland in 2016. Almost everyone else left in these playoffs does not. Siakam was on the Raptors team in 2019 that won it all, Dallas’ Markieff Morris was on the Lakers team that won in 2020 and Holiday was on the Bucks’ title team in 2021.

The pressure ramps up now. It’ll ramp up again on June 6 when the NBA Finals start. It shall be seen which of the young stars are ready to take the last — and biggest — step.

“It showed us who we are,” Edwards said after Minnesota ousted Denver in Game 7 on Sunday.

The Celtics were supposed to be here; they were the favorites entering the season and are bigger (-150) favorites now. Dallas was +4500 to win the title at one point this season; the Mavericks are +500 now, according to BetMGM Sportsbook. Minnesota started the year at +6600; the Wolves are now +260. And it seems like nobody saw Indiana coming; the Pacers’ championship line was +25000 entering the season. They’re +3000 now.

“We’re the uninvited guest,” Pacers coach Rick Carlisle said. “So here we are.”

He’s right. The youngsters from Indiana – along with the young stars from Boston, Dallas and Minnesota — have crashed the party. In fact, they have taken over the whole party. One of those clubs will be the newly crowned NBA champions, the sixth different one in the last six years, matching the longest run of parity in league history.

The old guard of the NBA isn’t done yet. But the new class sure seems like it’s ready for prime time.