The first proposal in London's Olympic Stadium took place today and, to the delight of the 20,000-strong crowd, she said "yes".
Charity mascot Wendell Raphael was shown onto a stage, his face beamed onto a big screen, after participating in a parade around the ground.
Thanking his girlfriend for her support of his charity work, Mr Raphael, 40, dressed as a super hero, then said: "This is not an April Fool. Bindi Bhambra, will you marry me?"
She was shown in tears watching from her seat and, to applause from the crowds, nodded her head to say "yes" as the words "She said yes!" flashed onto the screens.
Mr Raphael, known as Raph, who is from New Cross said: "When it was confirmed I'd be taking part in the parade two weeks ago, I knew I wanted to propose in front of all these people here today."
He met his fiancee, a 35-year-old teacher from Bristol, on a dating website six months ago.
Mr Raphael, an IT worker, also took part in a race at the new stadium during today's Gold Challenge charity test event.
He acts as mascot Super Donor Dan - wearing a red outfit and matching cape - for the African Caribbean Leukaemia Trust to raise awareness of blood and bone marrow donation, and donated a kidney to a friend in 2007.
Asked when the wedding might be, he said with a smile: "I want her surname to be Raphael as soon as possible."
The Gold Challenge sees members of the public compete alongside celebrities and sporting stars. Around a thousand people got the chance to take part in the key test event at the Olympic stadium earlier today.