Zayd bin Wahb narrated: Sayyiduna Abdullah bin Mas'ud (may Allah be pleased with him) and I entered the mosque while the imam was bowing, so we also bowed. Then we kept walking until we were level with the row. When the imam finished, I stood up to make up (the rak'ah), but Sayyiduna Abdullah (may Allah be pleased with him) said: "You have caught it."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 9322