The "Hunger Games" actress joined the host via telephone on Monday, after Ellen revealed that before becoming famous, Lawrence used to imagine being on her show while using the restroom.
"As the show is winding down, I got a lot of sweet messages from people and one of whom was Jennifer Lawrence. Not to brag, but we're neighbors," DeGeneres revealed. "Jennifer told me how sad she was that the show was ending and that when she was a kid growing up in Kentucky, she used to sit on the toilet and pretend that I was interviewing her."
"I thought, well, I can't end the show without doing that. She's on the toilet right now and I am going to call and interview her," she added, before doing just that.
Lawrence picked up, presumably sitting atop her porcelain throne. As Ellen noted, J-Law recently welcomed her first child with husband Cooke Maroney and baby duties kept her from making any in-person appearance on the show.
"Congratulations about the everything, the marriage, the baby, congratulations for everything. And this is a full circle moment. People don't know this, but I used to live in the house that you live in now when I started this show 20 years ago," Ellen then revealed. "So, now I live next door to you and I'm looking at you living in my house with a brand new baby when I started this show 20 years ago."
DeGeneres seemingly -- and accidentally -- revealed whether Lawrence welcomed a baby girl or boy, telling her, "By the way, I do hear you sometimes talking to him and it's really cute. It's so sweet." Other than share an "Aww" over the comment, Lawrence had no reaction to the apparent slip.
After sharing that she also used to imagine being interviewed by Oprah Winfrey and David Letterman, Lawrence added, "but I was really into your show, so every time it was a #2, it was you." She joked, "I really manifested hard on there, maybe that's the lesson. Take your time. Don't rush it!"
When asked what she thought Ellen would ask her during her "formative years on the toilet," Lawrence shared, "Probably just like, 'How did you get so pretty? You're the prettiest person I've ever seen,' and I'd be like, 'Ellen, stop, I'm definitely not the prettiest person you've ever seen.'"
That wasn't quite what DeGeneres had in mind for her very last interview with Lawrence ever, however, and ended the interview by asking her to reveal a project she was "devastated" she didn't land.
"Tim Burton's 'Alice In Wonderland,'" answered the actress. "I went in and was speaking in a British accent, thinking there's no way they'll find out I'm not actually British. So when I didn't get it, it was like a failure on all sort of fronts."
Ellen's show wraps up this week for good -- with the final episode airing Thursday, May 26.