‘Abdallah b. Mas'ud said he never saw God’s messenger observe a prayer out of its proper time with the exception of two, the sunset and the evening prayer, which he combined, and the dawn prayer which he observed that day(i.e. al-Muzdalifa) before its proper time. Bukhari and Muslim.

وَعَنْ عَبْدُ اللَّهِ بْنِ مَسْعُودٍ قَالَ: مَا رَأَيْتُ رَسُولَ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ صَلَّى صَلَاةً إِلَّا لِمِيقَاتِهَا إِلَّا صَلَاتَيْنِ: صَلَاةَ الْمَغْرِبِ وَالْعِشَاءِ بِجَمْعٍ وَصَلَّى الْفَجْرَ يومئِذٍ قبلَ ميقاتها