Roles in the episodes
In her first appearance, Diana Parker is first seen visiting her young sister, Trudy Proud for a couple of days from New York in her home. She brings toys from Paris for her nephew and niece, BeBe and CeCe, diamond starts from Amsterdam for Trudy and Suga Mama (which she mistakes for fake ones at first), a portable DVD player for her favorite niece, Penny, and finally, a book of brain teases from Russia for her brother-in-law, Oscar Proud.
When Penny returns from school, she tells her Aunt Diana that she got the role of Juliet from William Shakespeare's play, Romeo and Juliet. Remembering when she first played Juliet when she was Penny's age, Diana recites Juliet's lines perfectly in front of the whole family as Penny joins along as well. Then, she tells Penny that she is destined to follow in her footsteps as an actress.
Later, during rehearsals, Diana enters the school auditorium and acts perfectly as play director to Penny's friend, Dijonay when she doesn't seem to get her lines right. The school drama teacher and director, Mr. Randolph Verascola is amazed when he recognizes her as the famous actress and praises and welcomes her in as the students give her a round of applause. When Oscar enters and gets jealous when the director praises Penny for being related to Diana, the director tries to remove him with security (Moose and Rocco) until Diana assures the director that he is simply her "buffoon driver"; much to Oscar's annoyance, so, the director releases him. Then, the director tells Diana that he would be honored if she were to direct the play, which is why she came here in the first place and which she accepts. The moment she mentions the word "marry" concerning Penny and Kwok's roles when directing the play, Oscar naively gets mad, which makes Diana want to call security again and make Oscar flee for the exit.
Later, Diana and Penny (and Oscar) return after the rehearsals and after buying a beautiful dress for Penny's play; thanks to Diana's French costume designer, Pierre despite Trudy already having tried to make one for her herself with Suga Mama's help and much to her upcoming jealousy. Then, she goes to help Penny try it on. Suga Mama suspects she doesn't mean well and only cares about herself but Trudy believes otherwise since she thinks that it's just "the Diva in her."
After Penny discovers Kwok, whom she shows to have romantic feelings for, is to be married due to a Chinese tradition and refuses to go to the play, Diana decides to talk to her and give her something in order to convince her otherwise but Trudy insists she does it since she feels that her sister is taking over the mother role, which leads to Trudy finally standing up to her older sister, so, she tells her and Oscar to go while she talks to her daughter; much to an impressed Suga Mama's amazement.
After her mother convinces her to participate in the play (even before LaCienega tries to take her role), Diana is glad to see her but announces that she has to fly back to New York since her agent called and the rating for the show she's starring in is tomorrow morning. Then, she gives her a heart-shaped locket (inscribed "Your mother loves you very much. Listen to her. Love, Aunt Dee."), compliments her new dress, and leaves after kissing her good-bye.
In her second appearance, Diana is first seen arriving with her parents, Dr. Vincent and Maureen, her brother, Reuben and his family: his wife, Leslie and his daughter, Chanel in Reuben's SUV truck at Trudy and Oscar's house for BeBe and CeCe's baptism since it was Penny's idea in the first place.
Diana greets Penny and Trudy. Later, Diana is introduced to Oscar's country cousin, Ray Ray Proud and his family: his wife, Boonnetta and their sons, Ray Ray, Jr. and S'mo, whom Oscar invited for the baptism; thanks to his older brother, Bobby, who seems to have crush on Diana despite her disgust.
With so many relatives staying in the same house now, Oscar and his family are forced to sleep in a tent. Later, Diana and the rest of the families join Oscar and his family for dinner when Oscar calls them down. However, their dinner is interrupted by Penny saying grace and Ray Ray, Jr. and S'mo having eaten everything. Luckily, Oscar knows a place where they can all eat, The Red Clam, and he promises to pay. During the dinner at the restaurant, a family food fight occurs when Dr. Parker starts fighting with S'mo over a lobster and calling him a baby behemoth.
The next morning, at the Proud/Parker family picnic, Diana and her family are seen arguing with the Proud family over a game of Red Light - Green Light. Later, Diana Parker and her family are playing touch football against the Proud family, where they win at the end through cheating by having their pet Dachshund, Coco win for them, which leads to yet another family fight and argument.
After Penny, Chanel, and Ray Ray, Jr. are caught driving the mind-reading SUV truck by Sunset Boulevardez while on their way to the mall and to get away from their feuding families, another family argument and fight breaks out when each family member accuses either child for the idea in the first place, which eventually leads Diana and her family to leave despite her father feeling sorry for not attending the twins' baptism. Then, Ray Ray and his family leave.
Luckily, Penny is able to convince Diana and her family that Ray Ray and his family have left and vice versa, which convinces them to attend the baptism the next day. In the morning, at the church, Diana and her family are mad to see Ray Ray and his family having arrived as well, which leads to another fight until Penny silences them and Chanel and Ray Ray, Jr. join her to remind them how ridiculous they've been acting and what family really means to them, which leads to both families finally reconciling and making amends. Nevertheless, Diana stills shows some disgust of Bobby's continuous flirting.
At night, all families are having a peaceful dinner at the Proud family's home until Ray Ray, Jr. and S'mo start fighting over some pudding, which leads to yet another food fight but a little bit friendlier and amusing this time.
- Diana is Penny’s only relative on her mother’s side who has made more than one appearance in the show.