Olly Murs poses in his vest backstage at Coronation Concert

“I’m not going to take my top off, I have to be professional!” Olly Murs shows off his toned arms as he poses backstage in his vest at Coronation Concert after vowing not to go on stage shirtless

Olly Murs showed off his muscular arms as he prepared to perform at the coronation concert to be held in the grounds of Windsor Castle on Sunday to celebrate the coronation of King Charles III.

The singer, 38, was interviewed before taking the stage in front of King Charles III and Queen Camilla, as well as a crowd of 20,000.

While Olly was happy to show off his muscular physique behind the scenes, earlier in the day he insisted that he not pull off his top during his performance.

When invited to perform, he said on BBC Radio 2: ‘It’s a bit surreal, but I’m so honoured. I’m currently on tour, so yesterday I saw the stage. It’s the biggest in my career.

“It has the eyes of the world on it. This is something people will remember. It’s really special. It’s crazy. We just got an email asking me to do it!’

Looking good: Olly Murs, 38, showed off his toned arms as he prepared to perform at the Coronation Concert in the grounds of Windsor Castle

Born to perform: The singer was interviewed before taking the stage in front of King Charles III and Queen Camilla, as well as a crowd of 20,000 people

Born to perform: The singer was interviewed before taking the stage in front of King Charles III and Queen Camilla, as well as a crowd of 20,000 people

When host Dermot O’Leary joked that he looked muscular, Olly replied, “I’m not taking my top off, I have to be professional.”

Sunday’s show at Windsor is hosted by Downton Abbey and Paddington star Hugh Bonneville.

Buckingham Palace has promised “global music icons and contemporary stars” for the big concert.

It will undoubtedly be the highlight of the second day of coronation celebrations.

Around 20,000 audience members are expected and there has been much speculation as to who will be performing.

Musicians including Lionel Richie, Paloma Faith, Olly Murs, rock guitarist Steve Winwood and Nicole Scherzinger of The Pussycat Dolls will entertain the royal family and the public.

Classical acts such as Andrea Bocelli, Welsh bass-baritone Sir Bryn Terfel and Chinese pianist Lang Lang are also on the programme.

Hollywood star Tom Cruise, Dynasty actress Dame Joan Collins, adventurer Bear Grylls, singer Sir Tom Jones and former Strictly Come Dancing professional Oti Mabuse will also be featured via video.

Dressed to impress: Olly looked smart as he walked the red carpet wearing a white suit prior to his performance

Dressed to impress: Olly looked smart as he walked the red carpet wearing a white suit prior to his performance

Regal: The king and queen are seen waving by the crowd from the balcony of Buckingham Palace after the coronation on Saturday

Regal: The king and queen are seen waving by the crowd from the balcony of Buckingham Palace after the coronation on Saturday

The series of pre-recorded skits reveals little-known facts about the monarch and also features moments from beloved literary character Winnie-the-Pooh – seemingly echoing the famous moment Paddington Bear had tea with the Queen during her Platinum Jubilee celebration.

Nigerian singer Tiwa Savage, DJ Pete Tong with his project Ibiza Classics and winner of the talent show The Piano TV, 13-year-old Lucy, will also perform.

Meanwhile, fashion designer Stella McCartney will give a spoken-word performance on the theme of conservation that will reflect her and the king’s “shared passion for environmental sustainability,” according to the BBC.

Her performance will be part of a wider nature-themed portion of the concert, which will also feature a rendition of an 1980s hit by classic soul composer Alexis French and London-based singer-songwriter Zak Abel alongside a resident orchestra, band and choir.

Event: Guests are seen gathering at Windsor Castle, Berkshire, where the coronation concert is held to celebrate the coronation of King Charles III and Queen Camilla

Event: Guests are seen gathering at Windsor Castle, Berkshire, where the coronation concert is held to celebrate the coronation of King Charles III and Queen Camilla