LONDON--Scottish singing sensation Susan Boyle was tipped to give "the performance of her life" in the final of "Britain's Got Talent" Saturday but talk is rife that the pressure may prove too much for her.

Boyle, a 48-year-old spinster who has been catapulted to world superstardom in under two months, is runaway favorite to win the talent show even though her recent erratic behavior suggests she is feeling the strain.

Earlier this week, the church volunteer lost her temper in the foyer of the London hotel where she is staying and police stationed there intervened.

"Britain's Got Talent" judge Piers Morgan says she has considered quitting and was finding it "very, very difficult to cope and to stay calm".

"She has been in tears many times during the last few days," he wrote on his blog. "Susan Boyle has never experienced anything like this and is like a frightened rabbit in headlights."

"On The Edge" was the frontpage headline on Britain's Daily Mirror newspaper Saturday which, like many tabloids, led on the "health fears" over Boyle, who was starved of oxygen at birth and has mild learning difficulties.

The paper reported she would be monitored by medical experts including a counselor when she goes on stage Saturday. But she is still tipped to win.

Morgan wrote after the last "Britain's Got Talent" semi-final Friday: "My bet is that she will respond with the performance of her life at the final.

"This is one tough lady who has had to fight since the day she was born and there is no way she's going to quit now."

Frumpy-looking Boyle found fame when her performance of "I Dreamed A Dream" from the musical "Les Miserables" at the "Britain's Got Talent" auditions last month became a YouTube hit worldwide, attracting some 100 million hits.

Her second appearance on the show, in Sunday's semi-final, was less sure-footed. She sang "Memory" from musical "Cats" but was occasionally out of tune and out of time, prompting a Boyle backlash in the British press.

In a Daily Mail interview Saturday, Boyle said she had used singing as a way of "boosting my confidence" and insisted she was still enjoying the experience.

"I've found the whole thing quite amazing and overwhelming. The attention's odd and it takes some getting used to, but it's nice," she said.

But psychologists have raised concerns. David Wilson, a former advisor on reality TV show "Big Brother", said Friday that if "Britain's Got Talent" was a university experiment, Boyle would have to be withdrawn because of the "emotional turmoil".

And Susie Orbach, therapist to the late princess Diana, wrote in the Guardian that Boyle's reaction was "understandable".

"Being adored and projected on to by millions of people is never an easy thing to digest. That kind of exposure is always double-edged," Orbach wrote. "This is still a culture in which we build people up and then we attack them."

Results are expected from 9:30pm (2030 GMT) and Boyle is 10/11 favorites to win with bookmakers William Hill.

"As far as we are concerned, she just needs to turn up to win this," William Hill spokesman Rupert Adams said.

There are 10 finalists in total, including Shaheen Jafargholi, a 12-year-old Iranian-British singer whose fans include pop star Lily Allen, and Stavros Flatley, a father-son Greek Cypriot duo with a comedy dance act inspired by Michael Flatley of "Riverdance" fame.

At least 15 million Britons are expected to tune in for the prime time show, clips of which will be posted on YouTube soon afterwards.

The winner gets to perform for Queen Elizabeth II plus a cheque for 100,000 pounds (115,000 euros, $160,000). Whatever happens, Boyle also looks likely to sign a lucrative recording contract.