"Scarlett and Sean are not dating, they have been friends for years," Johansson's representation told E! Online. "Nothing more, nothing less. They have been talking over the last few months regarding Haiti Relief and Scarlett's upcoming trip to Haiti as Oxfam's Global Ambassador."
Johansson and Penn, 50, were labeled an item in this week's Us Weekly tabloid, which claimed the couple shared a cigarette break and left 5 minutes apart from each other at a recent "Black Swan" party at the Sunset Tower Hotel in Los Angeles.
Penn and his ex-wife Robin Wright were officially divorced in August 2010 after being married for 14-years. The couple had a 19-year-old daughter and a 16-year-old son together.
Johansson and her husband Ryan Reynolds filed for a divorce in December 2010 after 2-years of marriage. The couple got married in September 2008 in Canada after dating for about a year. They had no children.
"After long and careful consideration on both our parts, we've decided to end our marriage," Reynolds' spokesperson had quoted the actor as saying. "We entered our relationship with love and it's with love and kindness we leave it. While privacy isn't expected, it's certainly appreciated."
Reynolds rang in the new year with Sandra Bullock, his co-star from the 2009 film, "The Proposal," sparking rumors that the two were dating. Bullock denied the rumors at the Golden Globe awards later that month.
"I think there'll be a collective sigh amongst women across the United States when I say he's not my lovah, he's just an amazing friend I've had for 10 years," the 46-year-old actress told NBC's Al Roker at the recent 2011 Golden Globe Awards. "I don't get his loving after dark."
Johansson is set to reprise her"Iron Man 2" role as the Black Widow and her alter-ego Natasha Romanoff in the spinoff film "The Avengers," set for release on May 4, 2012.