The two actors were seen exiting a concert, reports Radar Online.
They co-starred in 2009′s He’s Just Not That Into You. Divorced last month by Ryan Reynolds, Scarlett Johansson has been seen with several Hollywood actors, but denies any romantic relationship.
Justin Long has been in a relationship with actress Drew Barrymore for almost three years.
“They’re friends,” Johansson’s rep told People. “They’ve worked together [on He's Just Not That Into You]. They’re not dating.”
Witnesses say the two were being “flirty” in a “friendly” way during the concert.
“They’re just friends,” a source adds. “They’ve known each other a long time.”
See the pics HERE.