Diversifying doesn't mean that you should start doing things that you have no skills in. That basically results in the one-stop wedding shops, where someone promises to do your invitations, flowers, catering, cake and DJ duties too. That kind of situation usually results in mediocre work in one or more categories because you just can't spread yourself that thin.
That makes you look bad, and it won't work to build confidence in your services.
One excellent example of bad diversification is this Phillip Michael Thomas gem from the '80's. Now, I'll be the first to say that PMT might not be the best actor in the world, but I used to watch Miami Vice like everyone else, and he was okay. Not so for this foray into the world of music, however.
If PMT had decided to diversify into doing a play, or voiceovers for animation, or movies, that would make sense. It's the curse of the bloated ego that so many so-called "actors" think that because they have a job acting, they should also sing. That's a diversification fail.
If you don't believe me, watch the video. And make sure to check out the neck action at 40 seconds.
So if you want to diversify, make sure that you have the skills necessary in the area that you want to add to your repertoire. Make it relatable to what you already do. That makes sense in the way that a third eye in your forehead doesn't.