The 25 singer – who opened her world tour in Belfast, Northern Ireland, on Monday – made time to visit the home of seriously ill fan Rebecca Gibney, 12, mere hours before her second concert on Tuesday.
"I am in shock, I got my baby's dream to come true," the child's mother Tracy told Belfast Live shortly after the visit in Belfast's Short Strand area. "She was so nice – she could not have been nicer."
The proud mom continued: "Adele was sat beside her and she was talking to me and my other kid, she was so nice for wee Rebecca. I cannot put it into words what it means."
Pictures of the visit show Adele beaming with a big smile next to Rebecca, who has exceeded doctors' expectations after being given six months to live last year, the BBC reported. Throughout her struggle, Adele's music has inspired her to smile and sing along.
"It's amazing. I'll never forget it. And I do know that when Rebecca passes away she did get her dream come true," Tracy told the BBC. "It's made me feel like I'm the best mummy in the world which I never felt. Adele told me I was the best mummy in the world too."
The touching moment was the result of Tracy's months-long Facebook campaign to encourage Adele to visit Rebecca, who reportedly suffers from cerebral palsy and epilepsy and is blind. Although Adele's manager replied to her letters, she did not hear anything further about an actual visit.
That changed Monday when she made a last-ditch attempt and emailed Adele's team once more. The next morning, Tracy received an exciting phone as she sat in a hairdressers' chair.
"The manager called and said, 'Tracy, it's Adele's manager. I am getting back to you because Adele has seen ... Rebecca's pictures, and she was very emotional and she wants to come and meet your daughter,'" explained Tracy. "I shouted at the hairdresser, 'Get this off my head – I need to go.' I wanted to keep it private."
She added: "It is unbelievable her dream has come true. Adele was just so nice."
Rebecca is too ill to see Adele perform live, but as a parting gift, the "Hello" hitmaker offered the family tickets for her concert at the SSE Arena. (The tour will now move on to Dublin and Manchester before she returns to the scene of her recent winning night at the Brit Awards with a six-night run at London's O2 Arena.)
News of Adele's act of kindness has since spread through the nation like wildfire. Martin McGuinness, deputy first minister of Northern Ireland, tweeted, "Many thanks @Adele, [you're] a STAR In more ways than 1. #Rebecca xo."
And Niall Ó Donnghaile, the former lord mayor of Belfast, tweeted that the visit made Rebecca and "Tracy's year!!"
In typical Irish style, she later invited the singer to a casual celebration, tweeting, "Just to let @Adele know, we'll be having a few pints of stout in St. Matthews tonight. More than welcome!"