Lip synch marriage proposal goes viral

A video of a US man's creative marriage proposal has gone viral on YouTube notching up close to eight million hits.

Isaac Lamb, from Portland, Oregon, surprised girlfriend Amy Frankel, a choreographer, with what he billed as the "first live lip dub proposal".

The video begins with Mr Lamb's brother sitting Amy down in the back of a car with a pair of headphones and telling her to listen to a song.

Set to Bruno Mars' Marry You, the ensuing choreographed dance routine features about 60 friends and family members dancing and lip syncing through the streets.

It ends with Mr Lamb getting down on one knee to pop the question to Amy who, to the relief of all involved, accepts the proposal.

The happy groom-to-be later admitted he had been taken aback by the popularity of the video.

"To be honest it's a little overwhelming. I'm really, really, really touched by how positive people's reactions have been," he told The Oregonian.

"The love I genuinely feel for my fiancee has touched other people. I never expected this and I'm really amazed by the response. My intention was never to make a viral video.

"It's crazy. I thought friends and family would like it and I figured that's where it would end."