The 26-year-old actor pulled a miserable look in a number of photo opportunities, repeatedly striking a hand-to-hair pose with a tortured facial expression.
Later, at a special fan Q & A at Fox Studios, Rob evened out the grumpy vibes by happily posing with fans and signing autographs.
R-Pattz sparked attention after working hours too, heading out for dinner at new Potts Point Greek restaurant Apollo, followed by drinks with his entourage at Hugo's Bar Pizza in Kings Cross at 11.30pm.
The British star spent two hours in a sectioned-off area, drinking vodka with eight girls in his presence, The Daily Telegraph reports.
A source told the newspaper that "he seemed in good spirits", but "a bit tired".
The same source added that Joel and Benji Madden and members of US band The Black Keys also came out for drinks.
Meanwhile, Rob's girlfriend Kristen Stewart arrived in Tokyo yesterday after attending Katy Perry's birthday party in Los Angeles on Friday night.
The 22-year-old actress smiled, waved, chatted with and posed for photos with fans at Narita International Airport.
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