Action star Akshay Kumar and his current leading lady Sonakshi Sinha who set the cash registers ringing at the box office with their livewire performances in <em>Rowdy Rathore</em>, have been engaged in a tiff lately. Akshay, who threw a grand bash on Sonakshi’s birthday recently, is now at the receiving end of the belle’s ire. Trouble has been brewing, quite literally, between the two co-stars.