The Pretty Reckless rocker's role on the show has been reduced, but sources insist that it's a result of the story line rather than anything personal against the star.
The insiders told E! Online that the Grinch actress is contracted through to the seventh season and her character Jenny will feature in each series, just not every episode.
'Jenny isn't in college like everyone else, so it's hard to weave her into the central storylines,' a source said. 'We don't want to just bring her in to hang out at the breakfast table with Lily and Rufus and say a line or two - we want a reason to have her there.'
A second source contradicted reports that Momsen has few friends on the hit show.
'Everyone likes her,' the source said. 'Her absence really is driven by the story. Anything else is speculative.'
Representatives for Gossip Girl and Momsen have not yet commented on the reports.