The five-time GRAMMY winner performed at Wembley Stadium in London
on Thursday night, and reportedly
included a handwritten letter in the concert's program. In the message, the "Hello" singer reveals that her 2016 sold-out tour might have been her last. "So this is it. After 15 months on the road and 18 months of 25
, we are at the end," she writes. "We have taken this tour across UK, Ireland, throughout Europe, all over America and I finally got to go to Australia and New Zealand too. Touring is a peculiar thing, it doesn't suit me particularly well."