Jennifer Aniston and Courteney Cox's relationship is strained, sources told UsMagazine.com.
UsMagazine.com said Aniston is upset with Cox because she has been dating, but hasn't filed for divorce from actor David Arquette, her husband of 11 years.
Cox and Arquette separated in 2010.
"There's tension," one insider said of the Aniston-Cox friendship.
Aniston's ex-husband, film star Brad Pitt, famously went public with his relationship with actress Angelina Jolie just weeks after Pitt and Aniston broke up in 2005.
"She hates watching Courteney do the same thing," the Aniston source told UsMagazine.com.