United Kingdom, Dec. 17 -- Selena Gomez's voice changes when her throat "swells".

Fans of the 33-year-old beauty have speculated as to why her voice has noticeably changed during the course of her career, and Selena has now addressed the situation directly, explaining that her "throat kind of swells inside sometimes".

Speaking to her fans on Instagram, Selena - who has previously been diagnosed with lupus and bipolar disorder - said: "Yeah I've gotten this question a few times. The voice thing. So, sometimes when I'm on - nevermind ... There's no excuse. I don't really care.

"I think my point is, is that sometimes things happen. I get weird. My throat kind of swells inside sometimes. That's all."

Meanwhile, Selena revealed earlier thi...