Kristen Johnston returns as Tammy on Mom

Kristen Johnston, who previously appeared on Mom as the crazy locked-up Tammy Diffendorf, returns to the show tonight as she is now paroled. Christy, played by Anna Faris, believes that Bonnie, played by Allison Janney, is way over her head when she decides to let Tammy stay with them as she’s freshly out of jail. In