PRINCE William and Kate Middleton were treated to a night of Gary Barlow hits when the royal couple joined thousands for a concert in aid of royal charities.
William is known to be a fan of dance acts and R&B tunes but when he met the X Factor judge he encouraged the singer to bring the house down.
The Duke of Cambridge and his wife chatted briefly with Barlow, minutes before he stepped out in front of a Royal Albert Hall audience, and were joined by the Prince of Wales and the Duchess of Cornwall.
Royal watchers were treated to a first as William and Kate, and Charles and Camilla had never attended a joint public event together.
The singer told the second-in-line to the throne: "I hope you enjoy tonight and I hope it's not too loud."
William, who wore a smart lounge suit like his father, replied joking: "The louder the better, the louder the better."
Kate looked relaxed in her black Ralph Lauren jacket and black and grey patterned Zara dress costing £69.99 and matched with a pair of boots,
While Camilla wore an Anna Valentine jacket and dress.
When the royal couples took their seats in the royal box a huge cheer went up from the audience who got to their feet and the prince acknowledged the reception by smiling and waving a programme in the air.
The event will raise funds for Charles's charity the Prince's Trust and the charitable body William runs with his brother - The Foundation of Prince William and Prince Harry.
The show was the second of two consecutive nights at the Royal Albert Hall with both performances expected to raise £400,000 for the good causes.
After striding on stage to cheers the singer waved up towards his royal guests during the opening verses of The Greatest Day.
After the first few numbers, Barlow greeted William and Kate's party saying: "Good evening to our beautiful royal family", adding: "All the money goes to a fantastic cause so we're killing two birds with one stone."
He sung A Million Love Songs, Pray, Nobody Else, among other hits.
Strictly Come Dancing contestant Jason Donovan was one of the acts who appeared with Barlow along with Olly Murs, Lulu, and X Factor's Marcus Collins who is mentored by Barlow.
He said: "It's about celebrating obviously the Prince's Trust tonight, raising money for that first and foremost, but above all that I think it's about celebrating Gary.
"He's one of this country's great songwriters and entertainers and a great friend - I'm honoured to be here tonight."
During the concert William, Kate and Camilla could be seen clapping along to the music while Charles tapped his hand on the armrest of his chair.
After the show the royal couples met the performers and also chatted to supporters of the organisations benefiting from the two fund-raising shows and comic Peter Kay a big fan of the Take That singer, who was in the audience.
Barlow said after the show: "It's been great, both nights were amazing, people have been buying lots of merchandise which all goes to a good cause."
Olly Murs, speaking after chatting to William and Kate, said: "I thought the night was amazing and they knew what I was up to.
"William said some of their friends who had Justin Bieber posters on their walls had taken them down and put mine up."