Jennifer Aniston, Courteney Cox have "tension"?

Jennifer Aniston and Courteney Cox have reportedly experienced "tension" in their friendship in recent weeks.

According to US Weekly, Aniston is disappointed with Cox for spending time with male Cougar Town co-stars Brian van Holt and Josh Hopkins while still technically married to estranged husband David Arquette.

"Jen thinks Courteney is acting callous by running around with this guy but refusing to file divorce papers. Like she's playing mind games with David," a source told the publication.

Cox and Arquette announced their separation in October 2010 after 11 years of marriage, though the pair are apparently still attending couple's therapy in order to improve their relationship for the sake of their 6-year-old daughter Coco.

Arquette has confessed that he is sick of discussing his split from Cox and insisted that he only did so publicly in order to dispel rumours about their relationship in the press.

Cox previously denied reports that she was dating Hopkins, insisting that the pair are just friends.