Adele's voice got lower when she was pregnant.
The 'Hello' singer - who has three-year-old son Angelo with partner Simon Konecki - is finding her vocals are only just getting back to the way they were after it got "cleaner" and her range improved when she underwent throat surgery in 2011 and then got affected by hormones when she was expecting her son.
She said: "At the very beginning it changed, it was very clean. Obviously I used to smoke quite a lot so all the scars my voice had were gone, it was like a brand-new voice.
"I can sing a lot higher than I used to, and I can sing a lot lower. But also in pregnancy my voice got a lot lower, which is why 'Skyfall' is so low, I couldn't get up that high.
"But after gruelling studio sessions and wear and tear, it's going back, but in a good way I think."
The 27-year-old singer is proud of her James Bond theme, 'Skyfall', and though it doesn't feature on any of her albums, she admitted it was considered for her forthcoming new record, '25' during a "dry period".
However, she ultimately decided it would be a "bit lazy" to include the track.
Speaking to Graham Norton for her upcoming TV special 'Adele at the BBC' - which airs in the UK on Friday (20.11.15) evening - she said: "We did talk about it for a while but felt like we were ripping everyone off, I thought it was a bit lazy but we did consider it, when there was a bit of a dry period we were like, 'Oh let's put Skyfall on'."
Adele went on to win an Oscar in 2013 for the track and though she had a "really amazing" time, she was unable to let her hair down afterwards as she had to go home to her son.
She said: "It was really, really amazing. I had to go back and feed [the baby]. I think I definitely had an in and out burger but everyone else went [to the parties] and they had a laugh."
During 'Adele at the BBC', the chart-topping singer performed a number of her classic tracks and some new material, as well as chatting with Graham and even showing her comedic skills in a hilarious yet touching sketch.