Strictly Come Dancing's four new professionals are set to be introduced to viewers in a cinematic routine filmed alongside the returning cast. European cup winner Vito Coppola, Chinese national champion Carlos Gu, former Under-21 British national champion Lauren Oakley and Latin dance champion Michelle Tsiakkas complete the show's largest-ever line-up of 20 pros this year.They join the returning Dianne Buswell, Nadiya Bychkova, Graziano Di Prima, Amy Dowden, Karen Hauer, Katya Jones, Neil Jones, Nikita Kuzmin, Cameron Lombard, Gorka Marquez, Luba Mushtuk, Giovanni Pernice, Jowita Przystal, Johannes Radebe, Kai Widdrington and Nancy Xu.The introductory routine will form part of the Strictly Come Dancing launch show airing on BBC One and iPlayer on 17 September.