Credit: Lester Cohen/

Despite Internet rumors, Jennifer Love Hewitt and Jamie Kennedy, who costar on the CBS drama The Ghost Whisperer, are still going strong, his rep tells

Citing "impeccable sources," blogger Perez Hilton has claimed that Kennedy, 39, "has been cheating on Jennifer Love Hewitt with his ex-girlfriend, Shannon Funk."

But a rep for the actor tells Us: "This is a completely fabricated story made up by a disgruntled former employee, terminated for cause. Jamie and Jennifer are happy and still together."

Kennedy also took to his Twitter page to slam the rumor about his girlfriend, 30, writing that it was completely "untrue and slanderous."