The new campaign is being filmed in London, and is being created by Rainey Kelly Campbell Roalfe/Y&R.
It is in the same vein as previous womenswear campaigns for M&S where Twiggy and O'Connor, along with Noemie Lenoir and Laura Bailey, are shown trying on lots of clothes as they get ready for an event.
The models have been shot recreating the cover of The Beatles' 'Abbey Road' - although the photos were taken in Greenwich rather than in St John's Wood, where the original was shot.
A spokesperson for M&S said the ad campaign would not be seen until September but there was no definite date for release at the moment.
After the first campaign appeared a year ago, M&S said that its clothes had been "flying out of the store", helping to arrest a decline in non-food sales at the high-street chain.
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