Boyle wept on meeting fans

Susan Boyle broke down while meeting fans in New York.

Fears are growing for the star’s wellbeing after she started behaving erratically after a performance at the US capital’s Rockefeller Centre.

Susan, 48, was in tears and shaking after fans handed her a gift, and was later seen sucking her thumb and staring into space.

Spinster Susan – who shot to fame earlier this year after a video of her singing on ‘Britain’s Got Talent’ became an internet hit - has already struggled to come to terms with overnight success, and completed a stint in The Priory rehab clinic after the reality show on which she found fame ended.

Her latest emotional overcoming came during her present short US tour, when she was handed a patchwork quilt stitched by hundreds of people from 28 countries, including the UK, US, Mexico, Japan and Poland.

A source told the Daily Mirror newspaper: “Everyone around her is acutely aware how susceptible she is to becoming emotional when under stress. She has just undertaken a tour of America, which would put anyone under enormous pressure.

"It seems to have taken its toll and she was visibly upset. She is being closely monitored and given all the support she needs."

Susan’s debut album, ‘I Dreamed A Dream’ has become the biggest advance selling CD in history, and is tipped to sell a million copies by the end of its first week of release on Sunday.

Speaking on The Today Show, for whom her New York performance was recorded, Susan said: “It feels very surreal, as if it’s not really happening, but it’s always important to stay grounded.”