Hugh Hefner, Nathan of The Wanted Credit: Courtesy of Playboy

"Glad You Came," indeed!

To celebrate band member Nathan Sykes' 19th birthday, The Wanted hit up the Playboy Mansion in the Holmby Hills of L.A. Wednesday. "It was a private BBQ birthday bash for Nathan and The Wanted after their appearance on The Voice," a source tells Us Weekly.

The Wanted's Max George, 23, Siva Kaneswaran, 23, Jay McGuiness, 21 and Tom Parker, 23, "were very sweet and excited" to be at the famed hangout, the source tells Us. "They even got to meet [Hugh Hefner]! This was something that was on their bucket list, so they were thrilled."

The source adds: "There was a DJ and they mingled with friends, Playmates and Bunnies, and they danced around the pool area." Glee's Chord Overstreet, 23, was also in attendance.

According to Sykes, he it was a birthday he'll never forget. "Thank you to everyone for all of your very kind birthday wishes," he tweeted Wednesday. "I had an amazing day so far and I can't wait to be back in the UK!"