George Clooney and fiancé Amal Alamuddin have been spotted taking a private tour of the castle from Downton Abbey, sparking rumours of a lavish wedding.

The pair visited Highclere Castle in Hampshire, which costs $24,000 to rent, last Thursday.

The glamorous couple are planning to walk down the aisle in September, almost a year since they met.

Clooney is said to be good friends with Hugh Bonneville, who plays Lord Robert Crawley on the show, and asked him to arrange a private tour.

According to a report by the Daily Mail, Alamuddin is huge fan of the TV show Downton Abbey.

While the location is still not decided, the Oscar-winner, who owns an Italian villa on Lake Como, is sure to choose somewhere extravagant.

Highclere Castle is the current home to the Earl and Countess of Carnavon and was built in 1839.