We got the EDM superstar at LAX Friday afternoon and our photog wanted to rave about his new song, "Waste It On Me," featuring K-pop group BTS. Steve's excitement was palpable after we brought up the track 'cause he could NOT wait to tell us the big news -- the track's a global success ... reaching No. 1 on iTune's global and U.S. charts. Sorry, Lady Gaga.

It's pretty incredible ... Steve and BTS dropped the track Thursday and in less than 4 hours it had more than a million streams on Spotify. What's more ... this is BTS' first all-English track. They've collaborated twice before ... but this one is something special.

Check it out ... Aoki also explains why BTS' crossover into the states is hugely significant.