The Twitter spat on Teacher's Day Thursday, was initiated by RGV, who took a dig at Karan's last directorial release "Student of the Year".
"If someone takes off from Karan Johar's 'Student of the year' and makes 'Teacher of the Year', it will become the 'Disaster of the Year'," Varma posted.
Karan did not take much time to respond, tweeting: "'Disaster of the Year' is your territory Ramu (RGV)...no one can ever replace the comfortable place you have made for yourself there."
Varma then tried to explain himself.
"Hey Karan, my tweet was in a series I put on Teacher's Day and that tweet was about someone taking off from you meaning it a compliment," Varma posted.
This wasn't the first instance of a war of words between the filmmakers, who style of filmmaking is as different as chalk and cheese. A popular Twitter fight between them happened in 2010 over Karan's movie "My Name Is Khan".