It is narrated from Sayyiduna Mu'adh bin Jabal (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) combined Zuhr, Asr, Maghrib and Isha in the year of Tabuk.
From the hadith of Amr bin Dinar it is gharib (singular); Uthman bin Umar alone narrated it.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 1814