As per TOI, it is none other than Sunny Deol's son, Karan Deol. Sunny says, "Karan's debut will be sometime next year. As of now, I want him to learn all the essentials required for being a good actor. We will be launching him but whether I will be directing him, I'm really uncertain. Considering we are still looking at scripts and everything is in its nascent stage. But one thing is certain that it will be a love story. That's the way I, Bobby and Abhay debuted in Bollywood."
Therefore, as per Papa dearest's wishes, Karan is enrolled in Rahul Rawail's acting school. Rawail had directed Sunny's blockbuster debut in Betaab.
Got to wait and watch how the fourth Deol boy fares in Bollywood.