Bring on the cake!

Arnold Schwarzenegger and estranged wife Maria Shriver put their differences aside to spend some quality time together for their son Christopher's 14th birthday.

The clan, including their two older children Katherine, 21, and Patrick, 18, dined at Mastro's Steakhouse in Beverly Hills, CA, Tuesday night.

Christopher is looking much slimmer since his boogie board accident this past July! The birthday boy left the upscale restaurant arm-in-arm with his mom and holding on tight to a cute card.

Maria made sure to stay close to all three kids while Arnold exited the restaurant with just leftovers in tow. Both appeared to be staying civil, but then again, they did have some practice being in each other's company this week -- just two days earlier, the separated couple had lunch with Patrick in Santa Monica.