Clooney's name on the licence reads as George Timothy Clooney while his lady love is listed as Amal Ramzi Alamuddin, reported Us magazine.
The marriage licences in London are prerequisite for a wedding and are apparently announced on a piece of paper behind a glass cover outside the town hall for all to see.
Clooney, 53, and Amal, 36, got engaged on April 28. They are reportedly set to have a winter wedding this year.