The Spice Girl-turned fashion giant was on the judging panel of the International Woolmark Prize which celebrates designs made from wool - a fabric that she has described as "one of the most special of all materials".
Six finalists from around the world competed against each other to win more than £67,000, the opportunity to have their clothes sold in shops such as Harvey Nichols in London and Bergdorf Goodman in New York, plus invaluable industry recognition.
Beckham, 38, was joined on the panel at the ME Hotel in central London by fellow fashion heavyweights Donatella Versace and Diane Von Furstenberg.
The mother of four, whose dress designs have been worn by stars such as Beyonce, Cameron Diaz and Jennifer Lopez, has admitted she is not afraid to cuddle up in some wool.
Christian Wijnants from Belgium was crowned the winner by the nine-strong panel of influential industry figures., beating fellow finalists Dion Lee from Australia, Ban Xiao Xue from China, Pankaj and Nidhi from India, designer duo Dressedundressed from Japan and Sophie Theallet from America.
Journalists and photographers were made to stand outside for almost two hours before they were allowed in to set up their equipment for Rihanna's show, a collaboration with River Island.
The show, at the Old Sorting Office in Central London, was due to start at 9pm but did not start until almost an hour later.
The music superstar swapped a catwalk for a stage separated into compartments which the models moved between to the sound of loud hip hop music.
The clothes on offer were of a raunchy street-style theme - with bra tops, dresses slashed to the thigh, tummy-baring tank tops and thigh-high boots.
Rihanna finally came out at the end to give the designer's customary bow and was dressed in a short black dress, sparking necklace and plenty of bracelets.
Here's a selection of other images from day two (Saturday) of London Fashion Week: