Miller dumped her one-time fiance in 2006 after it was revealed he had cheated on her with his children's nanny.
Despite almost four years apart, both stars have struggled to find lasting love - Miller ended her on/off relationship with actor Rhys Ifans, and endured a stormy romance with married actor Balthazar Getty, while single Law became a dad for the fourth time following a brief fling with American model Samantha Burke.
A rep for Law shot down reports he has been romancing Miller again after they were snapped enjoying a stroll together in New York City's trendy SoHo district at the beginning of November (09) - insisting they are just friends.
But the pair fuelled speculation again with a fun night out at Big Apple club The Box on Thursday (19Nov09) - and they only had eyes for each other, according to the New York Daily News.
A source tells the publication, "They came in together and got a table with a few friends around 1am. At one point, Jude ordered shots for the two of them, and he was egging her on to take one. They were laughing a lot and whispering to each other - it looked like they were genuinely having a good time.
"Jude's a regular at The Box and a lot of people know him there. So he had a ton of people coming up to say hi to him, many of them female, but he really only seemed interested in Sienna. It looked like he wanted people to see that they were together. They certainly looked like more than just friends."