Adele considered retiring because she was "frightened" to return to music.
The Hello singer worried nothing would match the global success of her 2011 LP 21 and considered walking away from her career forever while still on a "high".
She admitted: "I was scared. It got so out of control, the last album. I was a bit frightened for a while to step back into it...
"I didn't think I had it in me to write another record. I didn't know if I should. Because of how successful 21 was, I thought, 'Maybe everyone's happy with that being the last thing from me. Maybe I should bow out on a high.' "
The 27-year-old singer - who has a three-year-old son, Angelo, with partner Simon Konecki - eventually realised she needed to write songs just for her own sake.