The couple, who are thought to have reconciled after Pattinson, 26, forgave Stewart, 22, for cheating on him with film director Rupert Sanders, were attending a friend's birthday party together at the hotel on Saturday, reported Ace Showbiz.
"The couple snuck into the garden from a private side entrance. They were keeping their head down during this outing particularly because they're afraid of backlash, so they're keeping things on the down-low.
"Pattinson was hiding his face under baseball cap. He and Stewart were whispering very close and intimately throughout the evening," a source said.
