Once upon a time, trying to do the nice thing for her pals, Taylor Swift phoned the all-powerful show-runner boss Lorne Michaels with a request.

Her desire? She wanted “Saturday Night Live” to cut a sketch that would be making fun of her celebrity friend group.

Fast forward to this weekend and that story is making the rounds for a sound reason: The 50th anniversary of “Saturday Night Live” is going to be celebrated on Sunday evening in New York. …

And there are rumors Swift and Kansas City Chiefs boyfriend Travis Kelce might attend as part of the celebration praising SNL for its status as the longest-running comedy sketch show in history.

Present at NBC’s 30 Rock in New York City Sunday night will be almost every big cast member, guest host and celebrity who was ever involved in “Saturday Night Live” (and yeah, it is sort of weird that it is airing on a Sunday night. But whatever.

“Saturday Night Live” creator Michaels is offering some tales from the past as part of party, and Swift is involved in a doozy.

Ten years ago, Swift found herself in conflict with the show she had hosted once and served as musical guest multiple times.

Michaels said that in 2015, Swift called him personally to request that a sketch be taken out of the show.

The NBC program was working up a parody of Swift’s “Bad Blood” music video. The “Bad Blood” music video itself featured appearances from an assortment of Swift’s celebrity friends. The SNL parody would be a video showing them as part of an apocalyptic cult.

Those pals, by the way? Kendrick Lamar, Selena Gomez, Lena Dunham, Hailee Steinfeld, Gigi Hadid, Ellie Goulding, Martha Hunt, Cara Delevingne, Hayley Williams, Lily Aldridge, Jessica Alba, Ellen Pompeo, Mariska Hargitay and more.

Swift was asked to be in the “SNL” sketch. … but not only did she decline, she asked Michaels to dump it from the show.

“Taylor,” Michaels recalls telling her, “I do not negotiate with terrorists.”

The skit aired.

Swift’s relationship with Lorne Michaels and “Saturday Night Live” did not seem to be affected. She has made multiple appearances on SNL as the musical guest since that skit aired though she has not returned as host.

And maybe she’ll make another should she be in attendance at the 50th Anniversary special on Sunday evening.

The three-hour “SNL50: The Anniversary Celebration” show is set to air at 7 p.m. CT on Sunday night.