Alex Rodriguez and Cameron Diaz in Miami, June 6, 2011
12/15/2010 AT 12:00 PM EST
While in Miami for teammate Nick Swisher
's wedding to Joanna Garcia
, Alex Rodriguez
and Cameron Diaz
enjoyed lunch at the Soho House, then a romantic dinner at Prime 112. The two entered the restaurant together and immediately headed into a private wine room for dinner, where they ate with the curtains drawn. But an onlooker tells us, "At one point, Alex actually reached over and kissed her." And the whole restaurant "stopped and watched," the onlooker adds.