CARACAS (Reuters) - Fidel Castro joked about rumours circulating in the capital, Miami and on Twitter over the past few weeks that he was gravely ill or had died. The 85-year-old former Cuban president and revolutionary icon had been out of sight for two months until photographs published on Thursday and Friday showed him chatting with Venezuelan state TV commentator Mario Silva. Some of the shots, showing Castro having a bowl of soup and talking with Silva, were shown on Silva's regular late-night talk show while an audio of the interview was broadcast.