Oprah Winfrey kicks off her heels and reveals her painful bunion after Mandela's party

But as a tired Oprah Winfrey, 54, left the star-studded party for Nelson Mandela in bare feet, she revealed rather more than she planned to, as her protruding bunion was on show for all to see.

Queen of chat Oprah arrived looking glossy and groomed as she joined A-list friends to celebrate Nelson Mandela's 90th birthday last night.

Down at heel: Oprah ditches her heels after the Mandela party in London last night and reveals her protruding bunion

Big bump: The angry-looking bunion was obviously giving her some trouble as she partied in her high heels

But hours later, suffering from the dreaded sore feet that afflicts many a heel wearer, she finally gave in to the pain and kicked off her heels.

And on the short walk from her car to her Dorchester Hotel, Oprah's big bunion was unfortunately clearly visible.

Earlier at the party in London's Hyde Park, dressed in a white lacy blouse and long black skirt and her curly hair down, Oprah happily chatted to Will Smith, Uma Thurman, Denzel Washington, Bill Clinton and Gordon Brown.

Oprah triumphs in the auction at the star-studded dinner, as she sits alongside Sir Elton John, and Formula 1 racing driver Lewis Hamilton

Friends in high places: Oprah talks to Prime Minister Gordon Brown

Party girls: Oprah, Emma Thompson and Uma Thurman catch up at the dinner in honour of Nelson Mandela

Celebrity chef Gordon Ramsay prepared the banquet for the 500 guests, which would have been welcomed by Oprah, who just completed 21-day cleansing detox.

The star, who is famous for her yo-yoing weight, undertook strict three-week diet in an effort to 'jump-start an inner makeover.'

She followed Kathy Freston's book Quantum Wellness, cutting out caffeine, sugar, alcohol, gluten or animal products.

She admitted to almost giving into temptation, writing on her blog: 'I want some wine. Bordeaux 82. Just one glass at sunset, almost broke down and had a glass. I didn't.'

After completing the cleanse, she concluded: 'This has been exactly what we intended: enlightening.'

'I will forever be a more cautious and conscious eater. That's my commitment for now. To stay awakened.'

In celebration: Oprah with Nelson Mandela and wife Graca Michel at the party last night