The 18-year-old has been rated as the No.1 prospect for the US college class of next year and is a projected top-two pick for the 2016 draft, that is if he decides to leave Louisiana State University after his freshman season.

Simmons is in camp at the AIS in Canberra with the Boomers and is a strong chance to be included in the final 12-man squad for the World Cup in Spain from August 30 to September 15.

Standing 2.08m and with the ability to play the small forward or power forward positions, Simmons rose to prominence in the US after his performances for Montverde Academy, a high school in Florida.

That saw him invited as one of the top 80 high school and top 30 college players to the LeBron James Skills Academy in Las Vegas from July 9-12 this year.

Not content with watching from the sidelines, James – a four-time NBA MVP, dual-NBA champion and the best player on the planet – checked himself into the game to take on Simmons.

''We played a game and he was guarding me the whole time and I was guarding him, so it was fun,'' Simmons said.

''First time I met him, yeah I was awestruck because it was LeBron.

''I said 'what's up' and we talked a little bit.

''I saw him the next day at the camp and he said 'what's up' and he came on to the court, I didn't know what he was doing.

''I thought he was going to teach us something, then we started playing, we started matching up.

''I scored a few buckets, he hit one, we got a fast break, I dunked it ... it was a good feeling.''

Simmons is close friends with Boomers teammate Dante Exum and knows what to expect after seeing Exum's life change forever when he was selected by the Utah Jazz as the fifth pick at last month's draft.

"At the start of the year, it was kind of overwhelming, but I've gotten used to it, going to different events and camps,'' Simmons said.

''Getting to talk to LeBron and learning from him what he goes through every day has been great.

''I've learnt a lot the past year or two.''

Simmons got a taste of the international arena at a senior level when he played for the Boomers in last year's Oceania qualifying series against New Zealand.

Boomers coach Andrej Lemanis said the emergence of youth in the squad presented plenty of selection headaches. He will name the squad on Monday.

"One of the strengths we have is the depth of talent we have available to us,'' Lemanis said.

"There's a core group that's been through some experiences and we've added some exciting young talent to that.

''One of the great things, and the tough things as a coaching staff, is determining what the best team is.

"We've got 17 guys who can all legitimately claim a spot.''