Selena Gomez's voice changes when her throat "swells"

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 this year that she wants to "keep evolving".

The movie star has already achieved significant success as a singer and as an actress - but Selena has no intention of slowing down in the coming years, and she remains as ambitious as she ever has been.

The brunette beauty - who has been open about her mental health struggles in the past - told Allure: "I want to keep evolving and getting better in every area of my life. And I want to experience everything, so it's important for me to keep myself in check.

"I'm so stoked that when an emotion pops up, I'm able to acknowledge it and be a part of it, then let it go."

Selena has also enjoyed enormous success with her Rare Beauty make-up brand, with the company now reported to be worth more than $1 billion.

However, Selena is always open to new ideas and business ventures.

The chart-topping star - who married record producer Benny Blanco earlier this year - said: "I am going to be in this moment. And who knows, in a couple years I could be done, and that's fine. I just need to make sure that while I'm here, I do the best I can."