Musannaf Ibn Abi Shayba 3:3832

Waki' narrated to us, he said: Za'idah ibn Qudamah narrated to us, from Ali ibn Zayd ibn Jud'an, he said: I asked Sa'id ibn al-Musayyib about praying in a jubbah (outer garment). He said: And in the qamis (shirt), if it is thick.