Nicole Richie's Sexy Sushi Date

It's model-turned-actress Amber Valletta!

We didn't even know these two were friends but just this afternoon we spotted Nicole Richie and her latest BFF leaving a sushi restaurant in Santa Monica.

Although these two appear to be total opposites when you look at them (Amber's about a foot taller, even in flats!), in reality they have a lot in common.

Both are moms, and they both recently launched fashion lines (Nicole's Winter Kate - it's the silk cami she's wearing - and Amber's Amber Valletta for Monrow.)

Although unfortunately for us, they left their adorable children at home, but they looked as if they were engaged in a very animated conversation -- could this have been a business lunch? Are the two pals discussing a future collaboration?

Now that would be hot!