The estranged couple reunited yesterday when Kevin Federline went to visit Britney at Promises rehab center in Malibu. You can see security blocking photographers as Kevin's truck makes its way up Big Rock Road but X17 shooters were already in position and keeping an eye on Brit ...

According to our lensmen, Kevin brought some groceries with him and they met only briefly -- about ten minutes. But when KFed left, Britney headed out for a smoke and was smiling and chatting with a new friend she seems to have made at the treatment facility -- a woman about her age.

Maybe these parents of two are putting their differences aside and focusing on Britney's health and the welfare of the kids -- we can only hope!

We'll have new pix of Britney later today -- stay tuned!