'Not a dry eye in the house' one viewer of Sam Smith at the BBC said on Twitter, after the TV special showed Sam, 25, turning up to surprise brides Lisa and Bec on their big day.
Guests of the couple were left in tears too after the moving rendition of his ballad Latch.
Sam told host Fearne Cotton that it was the first LGBT wedding he attended.
Smith, 25, surprised the newly-weds at their reception and performed a moving rendition of his ballad Latch, and later told Cotton it was the first LGBT wedding he had attended.
“@samsmithworld we’ve all just sat watching you #SamSmithAtTheBBC and not a dry eye in the house!” one fan said on Twitter.
“Truly amazing talent…”
Another fan joked about being so moved by a wedding of a couple they didn't even know, saying “Highlight of my night was definitely crying watching a wedding of 2 people I don’t know.”