Rob and Ellen are a couple who are friends with Will and Grace. As tradition, they usually go to Will's apartment for game nights with their other friends Joe and Larry. Rob and Ellen have three children together, one of whom is named Roman.
In the episode An Affair to Forget, they announce their engagement and subsequently get married, and have at least five children.
Rob was Will's roommate in Columbia University. In 1985, he had been dating Grace's friend Ellen in college. Shortly after Will came out, Rob was one of the first people he told. Although he seemed shocked, they remained good friends after college that Rob serves as Will's accountant and Will serves as Rob's attorney. Interestingly, Rob is also somewhat homophobic that he easily becomes uncomfortable at being thought of himself as gay. During Will's toast at Grace's wedding, he vehemently yells that he's not gay.
After finding out Rob and Ellen are going to get married, Grace admits to Will that she and Rob had a one night stand years ago when the couple were having a fight and Grace had just broken up with Danny.
Around the birth of his first son, Ellen and Rob talk of moving to the city so they sublet Grace and Will's apartment.  However after a week, they decide it is better to raise their family back in New Jersey.
Ellen is Rob's wife who is also Grace's friend from college.
She and Grace were very close that, as Grace recalls whenever they would get into a fight in college, she would make Ellen a tunnel of fudge bundt cake and they would talk things through. Grace also recalls how Ellen supported her when her father was sick, and when she did not get into a Paris program.
Ellen first appears to have curly red hair. While during her first pregnancy, she stops coloring her hair, revealing her brunette roots. During her next pregnancy, she is shown to go back to her red hair. It is also said that she was 8 months pregnant at the time.
In a flashback to 1985, she has long curly blonde hair. Later in the series she dyes her short hair blonde again.
In A Gay/December Romance, it is revealed that her mother died when Grace called her about Happy Noodles.
- Grace notes that she is godmother to one of Rob and Ellen's kids.
- Rob and Ellen were named after producers Rob Lotterstein and Ellen Idelson who were also writing partners who worked on the show.
- The Truth About Will and Dogs
- Grace, Replaced
- Alley Cats
- Guess Who's Not Coming to Dinner
- I Never Promised You An Olive Garden
- An Affair to Forget
- Lows in the Mid-Eighties
- Poker? I Don't Even Like Her (Rob only)
- Someone Old, Someplace New
- Something Borrowed, Someone's Due
- Women and Children First (Ellen only)
- Marry Me a Little, Marry Me a Little More
- Sour Balls (Ellen only)
- Steams Like Old Times (Ellen only)
- Cop To It
- The Definition of Marriage (Ellen only)
- The Mourning Son
- Sweatshop Annie & the Annoying Baby Shower (Ellen only)
Ellen and Rob mostly appear together except when he appeared in Poker? I Don't Even Like Her and when she appeared in Women and Children First, Sour Balls, Steams Like Old Times, The Definition of Marriage, and Sweatshop Annie & the Annoying Baby Shower.