"Game Of Thrones" cast Kit Harrington takes on London's roof for the upcoming film "Spooks: The Greater Good" while his co-star in the HBO hit TV series looked very regal as she attended Prince William's charity event in Windsor Castle.

In a series of photos published on MailOnline, "Game of Thrones" cast Kit Harrington appeared to be so immersed with his role as Will Crombie while he tried to chase down a sniper on the roofs of London over the weekend.

The sniper seemed to have escaped (or died!) after jumping off the high roof. "Game of Thrones" cast Kit Harrington had a glum expression on his face while looking down below.

Kit Harrington plays Jon Snow, the bastard son of the Starks, in the HBO series "Game of Thrones." He has made a transition into movies with the disaster movie "Pompeii," which proved to be disastrous in the box-office as it made only $10 million domestically against the $100 million budget, The Hollywood Reporter noted.

In "Spooks: The Greater Good," Kit Harrington's character Will Crombie will partner with MI5 intelligence chief Harry Pearce to capture a terrorist who managed to escape. If they can't get to the terrorist on time, London is in danger of being attacked.

Meanwhile, "Game of Thrones" cast Sophie Turner joined Prince William for a charity event at Windsor Castle Tuesday. The 18-year-old Sophie Turner, who plays Sansa Stark-half-sister of Kit Harrington's Jon Snow-in the HBO hit, looked resplendent in a black one-shouldered gown showing off her milky white shoulders, MailOnline reported.

The dinner, sponsored by designer Ralph Lauren, was organized in order to raise more awareness for The Royal Mardsen Hospital, where Prince William is the president.

Other A-listers who attended the dinner were Benedict Cumberbatch, Cate Blanchett, Emma Watson and Kate Moss.