​Harry Styles congratulates Duchess Kate on her royal baby bump

Usually it’s girls who are nervous when they get to meet pop icons One Direction, but the roles were reversed when they met Duchess Kate on Thursday for the Royal Variety Performance at the Palladium Theater in London.

"It's the most nervous I think I've ever been in my life," One Direction’s Liam Payne told The Mirror.And Liam wasn't the only one, bandmate Louis Tomlinson was so jittery he forgot how to address the royal. "I didn't say 'ma'am,'" he admitted. "I said, 'Hi, How are you? I'm Louis.'"

But it was perhaps Harry Styles who was the most nervous, as he commented on Kate’s barely visible bump. "I said congratulations on the bump," the handsome singer said of meeting the soon-to-be second-time mom. "(Though) she didn't look bumpy."

Kate dazzled in an elegant black lace Diane von Furstenberg dress which she accessorized with a sparkly black clutch and blue topaz hoop earrings by Kiki McDonough, while wearing her shiny brown locks in a low chignon.

Prince William looked handsome in a classic tux at the event that benefitted the Entertainment Artistes' Benevolent Fund, which helps UK entertainers struggling with old age, poor health, or financial troubles. William was spotted hanging with the event's band and even told them he'd been "keeping a close eye" on their career.

The royal couple enjoyed the evening of music, theatre, comedy and dance from the London Palladium's Royal box. The entertainment included performances by Demi Lovato, Ed Sheeran and Ellie Goulding.

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