Got a thriving side hustle? Here's how and when to tell your boss about it — and why you probably should.

• Nearly 60% of adult US workers are likely to take on a second job next year. 
• Side gigs can be a source of ancillary income, but they can also take up a lot of time and energy.
• Experts say it's important to tell your boss about your side hustle. Here are some tips.

You've started a side hustle. (Congrats!) And it's going pretty well. (Go you!) It's probably time to tell your boss about it. (Wait, what?)