Do you ever get surprised when you see an actor play a role that's different than what you're used to seeing them do? Like a "tough guy" who shows up tap-dancing in a musical comedy?
It always takes me a few minutes to adjust to seeing them in this new role, but then I remember... he's an actor. And as an actor, he has varied interests and lots of training in different types of acting. Then it all makes sense: this guy I've seen play an action hero in movie after movie actually started out by singing in his 5th grade musical. And yes, he can also dance. It's just that his first big opportunity came in an action movie and then everyone else wanted him to play similar characters. Even though he enjoys playing these roles, he's continued to go to Broadway shows, sing and dance when he can, and generally enjoy the whole experience of acting, in many contexts.
You can insert any name you like into the above scenario, from Clint Eastwood to Johnny Depp. Old or young, male or female. Actors are actors, and having spent years playing piano for musical theater classes and Broadway shows, I've seen this scenario countless times. I remember accompanying Tony Danza onstage at Carnegie Hall. I knew Tony as the wise-cracking street kid on the TV show "Taxi." But there he was, 5 feet from my piano, tap-dancing and singing his heart out. He was having the time of his life!
Musicians are like this too.
I was reminded of this while reading a review of Elvis Costello's autobiography. Costello burst onto the music scene in the 1970s with a mixture of punk, new wave, rock 'n' roll that was utterly fresh and exciting. At the time, I was just getting into jazz and classical and wasn't very interested in his type of music. This was ironic, however, since over the years I've seen how Costello loves all kinds of music too. Sure, he became famous performing punk, but he was always interested in other genres of music as well. And he's gradually expanded his scope to bring this variety into his professional world.
He grew up hearing his father sing onstage and embraced a huge variety of musical styles, from jazz and the British music hall tradition to classical and cabaret. It turns out there was a whole lot more behind that raw, unpolished singer/guitarist all along!
The key point here is that musicians, like actors, don't exist in a vacuum. Sure, the public (and the music industry) like to pigeonhole their favorite entertainers into narrow roles ("He's a rock and roller." "She sings country.") But the musicians themselves are more varied than that. So use them as a model. If you want to excel at a certain type of music, be sure to listen to and learn a wider range of genres. Then bring all of this into your main focus and everything will be much more interesting that way. Have fun and good luck!