The Duke of Sussex, 39, was last week named as one of the recipients at this year's upcoming ceremony for his military experience and work on the Invictus Games.
The 14-time Grammy winner, 34, was performing her hit song "The Smallest Man Who Ever Lived" off her latest album when she got stuck on a raised platform mid-song.
The “Back to the Future” star left fans delighted after he appeared onstage in front of a 120,000-strong crowd at the annual music festival in England, UK.
"Although I fell in love with you the moment I met you, marrying you seemed like a dream," Alec, 66, wrote in a loving tribute to Hilaria, whom he married in 2012.