The band's frontman Oli Sykes says no one could have predicted that an 18-year-old singer would be pop's brightest star and he says mainstream music is made up of so many different genres nowadays that it's impossible to know who will be the next big thing.
Speaking to Absolute Radio, he said: "Billie Eilish is literally the biggest thing in music.
"The next 10 years it's going to be coming from all kinds of places.
"No one can know what the next big thing is going to be and I think that's dead exciting."
The 'Mantra' hitmaker added how BMTH like to "merge" the best of every genre into their own music.
He explained: "What we do is merge so many different sounds together.
"Everyone is looking for something new at the moment, everyone is looking for the next sound and I think the easiest way to do that is by taking what is good about every genre and putting it together."
Since ditching their death metal roots for a more mainstream sound, the 'Drown' group have been criticised by some of their fans for selling out, but Oli says they have "no shame" in mixing up their sound.
He said: "Some people just want to be purists and only like one style of music but for us there is no shame in that.
"Like why not put a bit of everything we are into and that we dig into what we do."