The blonde beauty was spotted with Long in Los Angeles on Wednesday attending a show by singer/songwriter Iron and Wine, but Johansson's spokesperson insists the relationship is strictly platonic, and gossip suggesting the pair is an item is false.
The representative tells People.com, "They're friends. They've worked together. They're not dating."
Johansson split from her husband, actor Ryan Reynolds, last year. Long is Drew Barrymore's on-off boyfriend.