Alicia Keys and One Direction entertain the Queen

Singing superstars Alicia Keys, One Direction, Kylie Minogue and Girls Aloud took to the stage in London on Monday (19Nov12) to perform at the 100th anniversary of the U.K.'s Royal Variety Performance.

Queen Elizabeth II and her husband Prince Philip, the Duke of Edinburgh, were also treated to songs by Rod Stewart, Neil Diamond and Robbie Williams at the annual spectacular, held at the Royal Albert Hall and hosted by funnyman David Walliams.

Classical singers Placido Domingo and Katherine Jenkins teamed up for a moving duet at the centenary show, the 36th attended by the Queen.

Girls Aloud star Nicola Roberts took to Twitter.com to express her delight after meeting the monarch, writing, "I'm so excited, I've just met the Queen. I've always wanted to meet her. She was sparkling from head to toe," while her bandmate Cheryl Cole added, "The Queen is so delicate. She has hair like candy floss and tiny little dancing style shoes. Awww."

Meanwhile, New York native Keys was thrilled to play the traditional U.K. show, insisting, "They showed me these amazing videos of different people performing at different times (for the Royal Variety Performance). Barbra Streisand I saw, Julie Andrews I saw. I mean, there's so many incredible legends who have been on this stage."

And Diamond added, "What an honor it is to sing for Her Majesty the Queen of England. A night to remember."

Every act in the star-studded line-up agreed to perform for free, and all proceeds generated will be donated to charity.