In the online-only show, which premiered last year, Lisa plays what she calls a "self-centered and ambitious" therapist, who helps her clients via Web sessions.
Courteney will play a rather interesting patient – one who happens to be a psychic.
The two were reunited on the Web-based comedy after Lisa called up her old pal.
"I asked her to be in it and she said, 'Sure I'll do anything," Lisa said in a clip to promote Season 2. "She's hilarious in a whole other way than [her 'Friends' character] Monica was and we just thought that would be fun."
Filming her guest spot came easy for Courteney, thanks to her former co-star.
"It was quick," Courteney said in a clip. "It was fast. She's a pro."
Scottish actor Alan Cumming, former "Brothers & Sisters" guest star Steven Webber and recent "Eli Stone" star Victor Garber are among the talent also joining Lisa for "Web Therapy's" Season 2, which kicks off Tuesday.
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