Who's Making Nicole Smile?

Nicole Richie - amusedIt seems that Jackass star Steve-O knows how to put a smile on Nicole Richie's face.

The super-slim socialite met the clowning stuntman for a lunch date in California, and couldn't stop giggling.

Nicole split up with fiance DJ 'AM' Adam Goldstein only last month - by mutual consent.

Could the smiles mean there's romance on the cards? Most girls do like a man who makes them laugh, after all.

However, Nicole did manage to keep a straight face long enough to sip Orangina and nibble some salad, you'll be glad to know.

And as they headed off, the pair made every effort to keep their distance to thwart the snappers.

What is Steve-O doing with his trousers?They nonchalantly walked away, leaving a fair old gap between them.

But Steve-O's casual trouser adjustment - as he kept a respectable 20 paces behind his 'date' - had Nicole in stitches.

We have all the pics here. Have a little looky yourself... and we'll keep you posted on whether these two are just mates or something more.