The pair, who are rumoured to have rekindled their on/off romance, were spotted at circus-themed night spot Cirque Le Soir, where the care-free couple kissed in full view of fellow patrons and seemed unconcerned about their public displays of affection.
A source said: "There's definitely no question about their romance anymore. Rihanna and Drake spent the whole night with their tongues down each other's throats and didn't seem to care about everybody seeing."
The rumoured couple - who arrived together but left separately - were treated to a sneak preview of Cirque Le Soir's latest acts as part of its new $800,000 Frat Party installation, which included a frightening clown sitting in a bathtub filled with baked beans, contortionist cheerleaders and cross-dressing prom queens.
Rihanna, 26, has been travelling with Drake, 27, across Europe in recent weeks while the 'Started from the Bottom' rapper performs in various cities on his latest tour.
The 'Take Care' collaborators enjoyed dinner together at London's exclusive Nobu restaurant on Saturday (08.03.14), arriving "hand in hand" before joining a group of friends.
Rihanna previously enjoyed a date with Drake in Amsterdam last week, and the pair visited Paris nightclub Soixante Dix Neuf last month.