The actors sparked romance rumours on 23 June (15), the eve of the Friday Night Lights star's 35th birthday, when they were photographed having dinner at exclusive restaurant French Laundry in Napa Valley, California.

Penn and Kelly, who reportedly met during a Haiti charity event, were joined by three other friends, who serenaded the birthday girl, and Penn even picked up the bill, according to

However, the usually private Kelly took to on Wednesday (15Jul15) to brush off the speculation, and wrote, "Not my nature to address gossip but hoping this last one goes away already. Not dating a friend I had a group dinner with. #Sillymedia."

The reported relationship comes a month after Penn's split from Hollywood beauty Charlize Theron in May (15). Kelly has previously dated Captain America star Chris Evans and baseball hero Derek Jeter.