Singer-actor Justin Timberlake and Mila Kunis were reportedly seen being very flirtatious with each other in London this week. Timberlake, 30, and Kunis, 27, are in the British capital to promote their movie Friends With Benefits. And the pair, who have been staying at the Dorchester Hotel, have fuelled relationship rumors once again after allegedly been seen getting cozy with each other around town. On Wednesday night, the Black Swan actress visited the hotel bar, The Promenade, where she began to perform some classic love songs. Timberlake joined her just ten minutes later and belted out some Frank Sinatra tunes himself. The stars then headed out together for some dinner at the China Tang restaurant - and apparently could not help but stare at each other. A source told British newspaper the Daily Mirror: "Justin couldn't take his eyes off Mila. "He was hanging on every word she said, and laughing a...