Scottish singing sensation Susan Boyle has pulled out of the Britain's Got Talent tour performance tonight in Manchester, Sky News has confirmed.

Insiders deny that Boyle'sabsence is anything more than a one-off rest day.

"Following three sensational performances, Susan Boyle has been advised to rest. She sends her sincere apologies to her fans for not appearing in Manchester."

But showbiz watchers believe there may be more to it.

"The pressure on Susan is incredible and at each show there have been about 5,000 people screaming for her," showbiz blogger Zoe Griffintold Sky News Online.

PHOTOS: Click here for photos of Susan Boyle.

Boyle became a worldwide star overnight after more than 100 million people watched her stunning Britain's Got Talentaudition.

But the 48-year-old Scottish spinster was then struck by emotion while staying at a London hotel after coming second in the final and was taken to The Priory clinic in North London suffering exhaustionon May 31.

She left the facility less than a week later and was reunited with her beloved cat Pebbles.

Blogger Griffin believes the other ensemble acts on the BGT tour have the benefit of supporting each other but Boyle does not have that luxury as a solo artist.

"Thousands are turning up to see Susan and when she is waiting in the wings it is not like the other acts who can encourage each other in the group," Griffin said.

Simon Cowell'spublicist, Max Clifford, tells Sky News Online about the plans in place to protect Boyle.

"I've spoken to Simon and his view is to take things very carefully with Susan as that is the most important thing," Clifford said.

"Everything relating to Susan is being done very gently and what everybody is concerned with is what's best for her and the plan is to take every day as it comes."

Click here to read more on this story from Sky news.