Neil Patrick Harris' wedding guests shocked by Elton John performance

Sir Elton John left guests in "disbelief" by putting in an unannounced performance at Neil Patrick Harris' recent nuptials.

The former How I Met Your Mother star wed longtime partner David Burtka in a castle in Perugia, Italy earlier this month (06-07Sep14), and among those present for the intimate ceremony was the legendary singer, who is close friends with the newlyweds.

During an interview with TV personality Meredith Vieira on her talk show on Thursday (18Sep14), Harris revealed that John was never meant to be the main attraction during their reception.

Harris explained, "He and (husband) David (Furnish) and their kids were coming as guests. And there was a piano player that was playing anyways, so I said, 'Would you want to just go up and play one song at some time?' And he said, 'Sure.'

"It turned into a much more involved thing - he sang three different songs. We kept it a secret so everyone that was there was just slackjawed in disbelief that Elton John was singing in a castle."

Harris described his big day as "fairy tale-ic", and that the ceremony turned out to be a much bigger to do than expected.

He added, "It wasn't super intentional. We wanted to have a destination wedding, so it eliminated having to invite hundreds of people... All of a sudden it turned into this really beautiful 50 person small intimate (ceremony)."