Messenger of Allah ﷺ offered the ʿIsha' prayer (and then got up at the Tahajjud time) and offered eight rakʿat and then offered two rakʿat while sitting. He then offered two rakʿat in between the Adhan and Iqama (of the Fajr prayer) and he never missed them.  

صَلَّى النَّبِيُّ ﷺ الْعِشَاءَ ثُمَّ صَلَّى ثَمَانَ رَكَعَاتٍ وَرَكْعَتَيْنِ جَالِسًا وَرَكْعَتَيْنِ بَيْنَ النِّدَاءَيْنِ وَلَمْ يَكُنْ يَدَعُهُمَا أَبَدًا