The Queen's guards at Buckingham Palace perform fun cover of Bon Jovi's 'Livin' On A Prayer'

They're notorious for being extremely serious, but it appears even the Buckingham Palace guards couldn't contain their excitement when Prince Harry joined forces with rock star Jon Bon Jovi for the Invictus Games Foundation.

Just hours after the Duke of Sussex — who recently decided to step down as senior members of the royal family — joined Bon Jovi at Abbey Road Studios in London to record the 57-year-old singer's single 'Unbroken' with the Invictus Games Choir, the Band of the Grenadier Guards treated onlookers to a rendition of the iconic Bon Jon Jovi song, 'Livin' On A Prayer'.

As the guards usually stick to ceremonial music, tourists who had gathered to watch the changing of the guard were pretty stunned, with many posting on social media about the moment.

Launched in 2014, The Invictus Games is a multi-sport event for wounded and injured veterans and servicemen and women.

The Netherlands will host this year's games, taking place from May 9 through May 16.

READ MORE:
• Prince Harry and Jon Bon Jovi recreate The Beatles' famous Abbey Road crossing photo
• The Queen has banned Prince Harry and Meghan Markle from using 'Sussex Royal' name

Harry returned to the United Kingdom this week for his final round of official royal engagements before he and wife Meghan Markle officially step down as senior working royals on March 31.

Meghan is set to join Harry in London next week.