Harry Styles, together with his bandmates Liam Payne, Zayn Malik, Niall Horan and Louis Tomlinson in One Direction, greeted Prince William and Kate Middleton on Thursday at the Royal Variety Performance, Palladium Theater in London.

They felt somewhat uneasy or a bit nervous on the idea of meeting the royal couple that One Direction guys behaved sheepishly as they exchange pleasantries. Payne shared that it was the most nerve-racking moment for him as well as for Tomlinson who forgot his royal manners and failed to address the Duchess properly. He immediately introduced himself without much ado, US Magazine reported.

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Clad in a Diane von Furstenberg black lace creation, Middleton's "baby bump" could be so visible that Styles greetings were directed to it. He said, "Congratulations on the bump," but admitted after that it did not look bumpy at all. Maybe he blurted out those words out of excitement to meet the Duchess.

Prince William also shared time with One Direction, telling them that he has been keeping an eye on their performance, The Daily Mail revealed.

Ellie Goulding, the royal couple's wedding singer in 2011 was also in attendance and will stage a performance together with One Direction, Bette Midler and Ed Sheeram.  It was also reported that the late Princess Diana's fave artist, Simply Red, is also expected to perform.

Queen Elizabeth and Prince Philip failed to attend this year's Royal Variety Performance although the event is intended for the Queen's charity institution, the Entertainment Artistes' Benevolent Fund.  On the other hand, it was the first time for Kate and Prince William to grace the affair.