MILAN, Oct 28 (Reuters) - Telecom Italia"s (TIM) top shareholder Vivendi (VIV.PA) has asked for an extraordinary board meeting at the Italian telecoms group to discuss the proposed reorganisation of TIM"s businesses, a source close to the matter said. TIM (TLIT.MI) declined to comment. The source said Vivendi, which owns 24% of TIM, expressed its request in a letter to TIM Chairman Salvatore Rossi on Thursday. The move comes after TIM on Wednesday cut its 2021 core profit guidance due to worsening conditions in its domestic market, piling pressure on CEO Luigi Gubitosi, who in February won a second term with backing from Vivendi and state lender CDP, another leading investor in TIM. A source close to Vivendi on Wednesday said the French group was committed to TIM over the long term despite the disappointing results and wanted to work with Italian institutions to help TIM achieve its goals. read more