Appearing on spoof documentary show After Lately, the Horrible Bosses actress met with Chelsea Lately staff writers to mock Handler's "busy" schedule.
"[Is she busy] gossiping about more successful people that are better-looking than her? Putting her name on another dumb book to make the world an even dumber place?" Aniston said.
"It's a shock that she really still has her own show! That little guy... the little one that she slept with to get the gig? He doesn't even work for the network anymore."
Aniston went on to claim that Handler is not the cleanest person, adding: "And then her hygiene... have you noticed this? Honestly, when we were in Cabo, she never showered! She would be like, 'What? I went in the pool'. It's gross!"
The former Friends star was recently reported to be expecting her first child with boyfriend Justin Theroux.
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Watch Jennifer Aniston discuss Chelsea Handler on After Lately below: