The 47-year-old actress graces the front of the publication's annual edition, following in the footsteps of last year's honouree Pink, and spoke about the tribute in an interview filmed for Wednesday's (April 24) episode of Ellen DeGeneres's chat show.
Seeing the cover flashed up on the big screen behind the host, Jennifer went red and giggled: "Oh there it is. Oh, gracious!".
The mother-of-three added she'd "never been more nervous than I am today", and explained: "I guess I thought you guys would boo. You know what I mean? Like you guys are expecting Kaia Gerber and it's me. I feel like bolting."
And when Ellen showered her with compliments, including "you're a beautiful person inside and out", Jennifer continued to struggle to hide her blushing complexion as she smiled: "It's so silly! But it's nice, thank you."
In her interview with People, Jennifer spoke about her style and make-up regimes, and also opened up about how her role as mother to Violet, 13, Seraphina, 10, and Samuel, seven - her children with ex-husband Ben Affleck - is changing.
"I'm starting to get to the point where I realise this job is not going to be forever," she mused. "Not in the all-encompassing every meal, every moment, every day way that I have loved for the last thirteen years. It's going to shift. But there's beauty in how it works in episodes."
Jennifer added that while her offspring are used to seeing her get glammed up for red carpet events or premieres, they are always keen for her to return to her "Mom" clothes.
"I'll feel like the best possible version of myself," Jennifer said of when she's dressed to the nines. "They'll look at me and say, 'Can you wash your face? Can you put your hair in a ponytail and put your glasses and sweats on?' And I see the compliment in that. They just want me to look like Mom."