Suffolk bride-to-be Tallulah Brown had a heart-stopping moment when the diamond to her engagement ring fell out on board a train.
But big-hearted passengers gathered together to search for the stone and found it within minutes with the help of the train guard.
Tallulah, a screenwriter from Aldeburgh, is engaged to Tom Allott, the son of TV presenter and broadcaster Anneka Rice.
Tallulah said: "Everyone was laughing and I was weeping, we were all weeping and it just felt so surreal.
"It was a proper movie moment and I just felt like it was a great thing for a stranger to do."
Tallulah had just had the ring resized and was on the train with her parents and made her way down the carriages to meet with Tom on their journey to Portsmouth Harbour from Haslemere at 6.30pm on Friday October 11.
Tallulah said: "When I realised that the stone was missing I knew it was on the train because I'd just spent the whole time staring at it.
"Me and my parents started panicking and Tom was trying to calm me down.
"We were on our hands and knees with a torch looking under seats and getting in people's way and then a lovely train guard came along and said he'd help us.
"So he got up and went on the loudspeaker and said: 'Ladies and gentlemen, there is a diamond on the train. Could you please have a look for it by your feet.'"
Just moments later the stone was found and the guard announced it on the loudspeaker.
"All of these people to come together to cheer for me it was amazing," she said.
"I bought the guy who found it a bottle of prosecco and we'll definitely have to give him a shout out at the wedding because he could have saved our marriage.
"What would have happened if that had been our first argument?"
Tallulah and Tom were en route to the Isle of Wight to celebrate their engagement and will be getting married next summer in Aldeburgh in a quiet church before heading to a friend's barn for the afterparty.
Tallulah added: "I only had that ring on my finger for ten minutes!
"Now I see it as a good omen though because it was stressful but so funny now we look back at it."
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