It’s been B-town’s best kept secret for very long but of late, the elusive couple appears to be throwing caution to the wind. After pictures of them together at the Mumbai airport not so long ago, Rani Mukerji was in London last week to celebrate her birthday with Aditya Chopra. A source from Yash Raj Films revealed, “For the past few years, Rani and Adi have been celebrating their birthdays and all important occasions together. With Adi currently stationed in London to look into his father’s directorial venture with Shah Rukh Khan, Katrina Kaif and Anushka Sharma, Rani decided to take a break from shooting for Anurag Kashyap’s Aaiya and flew down to London to celebrate her birthday on March 21 with Adi.” Reportedly, there was no elaborate party. The couple, along with Yash Chopra and Shahrukh Khan, went for a quiet dinner and spent some quality time together. The entire Chopra family has been staying together at a villa in London. SRK has a house there and so does Katrina. The source further said, “Rani also visited the sets of Yash Chopra’s yet-untitled film. He seems to have given his nod to the relationship, and rumour is that the couple will tie the knot this year.”