On Monday Bradley Cooper Cooper made an appearance on Jimmy Kimmel Live to promote Guardians of the Galaxy, and when the 39-year-old star waved to fans and photographers, we got a peek at a gold ring on his left ring finger. Funny, because we spotted his girlfriend Suki Waterhouse wearing a similar gold band on her left ring finger at LAX the other day, and we aren't the first ones to wonder whether the duo are engaged!

When the couple went to the Chiltern Firehouse in London earlier this month, they were seen wearing the same gold rings, and a source for Look magazine said the Hangover hottie gave his 22-year-old model girlfriend the ring "as a symbol of their commitment."

"Theres been some sort of intimate thing go down between the two of them," the source added. "Its been very private and didnt involve a formal blessing. Brad's been married before [to Jennifer Esposito for four months in 2007] so he's not setting a huge amount of store by making it 'official.' Suki's so head over heels -- and young -- that she's totally cool with this more hip arrangement."

The May-December couple have been dating since they met at the Elle Style Awards 18 months ago.