(Cover) - EN Showbiz - Mike The Situation' Sorrentino "isn't sober anymore", according to reports.

The Jersey Shore star entered rehab in March for substance abuse treatment but has allegedly fallen off the wagon since his release.

Sources claim the 30-year-old's sobriety lapse was triggered by the prospect of his hit MTV show coming to an end.

"[The Situation] isn't sober anymore," a source revealed to Us Weekly magazine. "Mike's freaking out about what he's going to do after the show."

This follows reports from last month that The Situation was seen drinking alcohol at the London West Hollywood hotel. A witness allegedly saw him "downing so many cocktails, he could barely stand."

The Situation's representatives have since denied the star has turned to alcohol.

"He has not been drinking," a representative told the publication.

The Jersey Shore star was admitted to a rehab facility for help battling his pain medication problems. In July he claimed detox had left him feeling like "a new person" who was "ready to conquer the world."

The final season of Jersey Shore premieres in the US with a double episode on MTV tomorrow. (C) Cover Media