A duvet and duvet cover combination where the duvet is arranged to be placed inside the duvet cover, where the duvet includes an integrated substantially rectangular extension part having a first long side attached to the duvet, and a second long side divided up in two parts that are separated by an aperture which extends essentially centered and over at least half the distance between the second long side and the first long side The duvet includes straps arranged in corners of the extension part and the duvet cover includes through holes arranged in corners of the extension part. The straps are arranged to be passed through the holes on the upper side and the under side of the extension part of the duvet cover whereafter they may to be tied together to keep the extension part of the duvet safely in place inside the extension part of the duvet cover, whereby the shoulders and arms of a user may be kept warm by the extension parts.