That was the situation at Avra Beverly Hills on Wednesday night -- where the newest L.A. Lakers star broke bread with two of the most powerful men in Hollywood.

And, get this ... it seems Leonardo DiCaprio tried to run interference for Al and Bron -- because after the meal, Leo went out the front while the other two guys went out the back!

Of course, Leo is a massive Lakers fan who's been a regular at Staples Center over the years -- maybe Pacino is a fan of "Trainwreck"?

BTW -- LeBron's business partner, Maverick Carter, was also there (in the jean jacket) ... so yeah, this dinner was more business than pleasure.

No word on who paid (or expensed) the bill.

It's Bron's second big celebrity dinner since he's come to town -- he had sushi with Khloe Kardashian and Tristan Thompson earlier this week.