Romantic Jonny Black, 43, popped the question to partner Kathryn Keir, 41, after finishing the Edinburgh Marathon in Scotland.
The keen runner had a personalized top made which read: “Kathryn, will you marry me?” on the front and “Popping the question if and when I reach the finish” on the back.
Shocked Kathryn was at the finish line cheering on boyfriend Jonny, who ran the race in four hours and 27 minutes.
And she managed to capture the whole proposal on her on phone, as she was videoing Jonny, from Dundee, Scotland, as he finished the race last weekend.
In the adorable video, Kathryn shouted Jonny's name before he turned around and walked towards her, ring in hand, and got down on one knee.
Jonny, a software engineer, said: "We met two years ago.
"I’d got invited by her to a post-Edinburgh Marathon prosecco party in Linlithgow so I thought it was an appropriate occasion to mark it.
“For the last couple of years we’ve been involved with the Linlithgow Running Buddies and done a lot of running together.
“Kathryn dropped me off at the start then I changed into the top at the start line.
“A mile before the end I prepared myself for what was to come.
“She had no idea at all.”
Jonny bought the stunning emerald engagement ring from one of Kathryn’s favorite jewelers in Linlithgow, West Lothian.
Exhausted from the 26.2 mile run, Jonny said he slowed down near the end to help compose himself for the big moment and was “relieved” when Kathryn said yes.
Jonny said: “I was just so lucky when it came to the finish, then she shouted my name.
“I was relieved she was there and it was just an amazing moment.
“I slowed down a bit and wanted to be fit enough at the end to get down on one knee and get back up again.
“I booked a hotel in Edinburgh and we had a nice meal - it was really good.
“It was an amazing day, absolutely perfect.
“I couldn’t have planned it any better.”
Jonny, who was running his sixth marathon, added: “It’s my slowest marathon yet but I don’t mind at all.
“I contacted Kathryn’s mom on Friday, two days before the marathon, and asked her.
“She was really emotional and delighted.
“The reaction from everybody’s been great.”