Sayyiduna Abdullah bin Amr (may Allah be pleased with them both) says: When the sun was eclipsed in the time of the Prophet (peace and blessings be upon him), it was announced: "The prayer is about to be held." The Messenger of Allah (peace and blessings be upon him) performed two bowings (ruku') in one rak'ah. Then he stood and performed two bowings in one rak'ah, then he sat, and the eclipse had ended.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب صلاة الخسوف / 6300