Sienna and Jude split back in 2006 after he got caught doing the nasty with his children's nanny, but Sienna held onto that huge chunk of bling after the engagement went kaput.
Sienna's pal told Life and Style magazine: "She wore it for fun, probably as jewelry. But she wore it with close friends, and everyone saw it - there's no denying it.
"They aren't engaged yet, but I wouldn't be surprised if she and Jude go all the way. She's very happy."
Sources close to the couple say they wouldn't be surprised if Jude pops the question again very soon because he doesn't want to lose her again.
A source said: "Sienna was always the one. And now she is back in his life he never wants to let her go again.
"He needs a good woman to look after him. Sienna's fed up of the single life and wants to be with Jude for good."
What do you guys think of these two reconciling? Is it gonna last? Or will Jude mess up again?