A major drawback associated with current hot or warm water-based bitumen extraction processes is the high consumption of energy. To address this issue, an aqueousnonaqueous hybrid bitumen extraction process (HBEP), in which a portion of the diluent (solvent) was added upfront to soak mined oil sands prior to its water-based extraction, was proposed and demonstrated to be feasible to process mineable oil sands at ambient temperatures. This study investigates the effect of adding ethyl cellulose (EC) as a promising demulsifier to the solvent on bitumen recovery and froth quality in the ambient HBEP. The laboratory flotation results clearly showed a significant improvement in froth quality with a negligible setback on bitumen recovery by 100200 ppm EC addition to the HBEP. Determined by an online visualization method, the addition of EC in solvent to the HBEP was found to further enhance separation kinetics of bitumen from sand grains of real oil sands ores. The addition of EC in solvent also increased the probability of bitumen droplet coalescence determined with a micropipette technique, but hindered the attachment of air bubbles to solvent-soaked bitumen, in particular at high EC dosages as evaluated by increased induction time of air bubble-bitumen attachment.