The 74-year-old Heptulla is a former deputy chairperson of the Rajya Sabha.
Irani, 38, is a Rajya Sabha member from Gujarat. She contested the Lok Sabha election from Amethi in Uttar Pradesh but lost to incumbent MP and Congress vice president Rahul Gandhi.
The four most prominent faces in the union cabinet are above 60 years of age.
They are Rajnath Singh and Sushma Swaraj, both 62 years, and Arun Jaitley and Venkaiah Naidu who are 61 and 64, respectively.
Another leader who is above 70 years of age is Kalraj Mishra. The former president of the Uttar Pradesh Bharatiya Janata Party unit is 72 years old.