Which other member of the Triple Alliance first supported Austria-Hungary's invasion of Serbia?

Germany was the other member of the Triple Alliance that first supported Austria-Hungary's invasion of Serbia. The Triple Alliance was formed between the countries Austria-Hungary, Italy and Germany. This Alliance was a totally military alliance with a single goal and that was to protect one another if attacked by any other country. This alliance was also their to support in case any of the members attacked any other country. This alliance was signed by the three countries on 20th of May 1882 until the break of the World War I in the year 1914.