Abstract: This invention discloses a system for in-stream advertising on an internet connected device comprising: at least a media streaming server adapted to stream media content in relation to a request from said internet connected device, said media streaming server further adapted to read and stream a concatenated file containing said media content and in-stream advertisement, on said internet connected device, in a single request from said internet connected device; at least an adinsert module adapted to concatenate said fetched advertisement and said media content; and at least a file writer configured to write said concatenated file containing fetched said media content and said in-stream advertisement in a single file in order to enable said media streaming server to read and stream said concatenated file on said internet connected device in a seamless manner.