"They looked very much like a couple, holding hands throughout the evening," an eyewitness told ET.
Later, the two were seen together at the NYLON Midnight Garden party. A press release from the soirée stated that Pine and Boutella "arrived on a double date with newlyweds Troian Bellisario and Patrick Adams."
However, a source tells ET that Boutella and Pine "are friends but not dating."
While the status of their relationship has yet to be confirmed, Boutella had no problem gushing over Pine over Instagram last September.
"With this special special human dear to me at 'Hell Or High Water' London premiere," she captioned a black-and-white shot of the two. "So proud of him ! Great movie great cast fantastic performances ! Don't miss it !!"