Andrea McBride (Tracy Nelson) is the villainess of the 2000 film The Perfect Nanny. Andrea lived under the care of her mother, an emotionally abusive woman who ran scams for a living. Andrea grew up odd, with her mother's emotional abuse only worsening Andrea's psychosis. Andrea grew up to be an emotionally unbalanced woman with a fixation for having a man love her, leading her to grow obsessed with a brand of romance novels. But Andrea's romantic life was less than she desired, leading to her attempting suicide after walking in on her husband Troy with another woman.
After spending time in a mental hospital, Andrea assumes the name Nikki Harcourt and applies for a nanny position placed by widower Dr. Robert Lewis. She secures the job after killing a fellow applicant by lying her way into the woman's home and pushing a bookcase onto her. She quickly bonds with Robert, along with his teenage daughter Fawn and young son Ben. She and Fawn both harbor resentment for Julia Bruning, a woman who works with Robert and who appears to be romantically interested in him. After hearing about a trip the two plan to take together, Andrea kills Julia by hitting her over the head with a rock while she swims in her pool. Elsewhere, Andrea's mother and Troy try to track Andrea down using her romance novel subscription.
After Julia's funeral, Fawn begins to notice Andrea's strange behavior, but her father disregards her concerns. Andrea goes on to kill Conrad, a rival of Robert's at the hospital, and she begins fantasizing about her and Robert playing the lead roles in her favorite novel. Troy eventually tracks Andrea down and forces her to leave with him. She asks him to pull over so she can use the bathroom and instead puts rocks in her purse. When Troy goes to look for her, Andrea hits him with her purse, knocking him off a cliff.
As Fawn is uncovering more of Andrea's secrets, Andrea prepares to seduce Robert when her mother unexpectedly arrives. She smugly insults Andrea, calling her "sick in the head", and demands that she support her financially now that she is close to the wealthy Robert. Andrea kills her mother by stabbing her in the chest, telling her to burn in Hell. She then hides her body in a closet before going to tell Robert how she feels about him. He rejects her while apologizing if he led her on in any way. Andrea snaps at Robert, angered that he won't love her after everything she'd done for him. As Robert almost discovers Andrea's mother's body, Andrea knocks him unconscious with a champagne bottle. When Fawn arrives, Andrea chases her with a knife before cornering her in Robert's office. Robert then shows up and feigns love for Andrea, saying that they can be together and that Fawn would learn to accept their relationship. Andrea breaks down in tears, drops the knife, and rushes into Robert's arms. Andrea is then sent back to the mental institution, where she has completely retreated into her delusional mind.
- Tracy Nelson also played psychotic villainess Alice Miller in The Rival.