Abu al-Juwayriyah (may Allah have mercy on him) says: I saw Anas bin Malik (may Allah be pleased with him), the servant of the Prophet (peace and blessings be upon him): when the imam began the sermon on Friday, he would turn his face towards the imam, and he would remain so until the imam finished his sermon.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الجمعة / 5714