The CRAZY IN LOVE singer - who had been feeling ill all day - performed her hit single at the Party In The Park gig before rushing off stage and diving straight into the nearest toilet.
And as Charles' helicopter approached, aides desperately tried to get the star together in time to meet him.
An onlooker tells Britain's DAILY STAR tabloid, "We saw her dive into the trailer as soon as she came off stage. And she wouldn't come out again.
"Her dad MATTHEW, who is also her manager, was trying to keep attention away from what was going on.
"But he privately admitted that she'd been feeling ill all day and had gone inside to be sick. He said it was nerves. She was terrified about the show - because it was her first ever UK solo appearance.
"And to make it worse, he said she was also nervous about meeting Prince Charles."
But the Prince didn't make it any easier on Beyonce - telling her his hunky son Prince William "fancied" her.08/07/2003 13:51