Styles told Rolling Stone in 2017 that he prepared to meet the iconic singer by bringing her a cake with her name "piped" onto it.
"She loved it," he said, adding, "Glad she liked carrot cake."
Nicks didn't forget Styles' generosity and revealed in 2017 that Styles had been "adopted" by her former bandmate Mick Fleetwood.
"Harry is that tall, lanky, musical son he always wanted, so they keep in touch," she said.
Since becoming friends, Styles and Nicks frequently perform together, with Styles covering Fleetwood Mac's "The Chain" on more than one occasion. And their friendship appears to be strong as ever, with Nicks calling Styles her "love child."
While inducting Nicks into the Rock & Roll Hall of Fame in 2019, Styles gushed that she's "everything you've ever wanted in a lady, in a lover, in a friend."
And speaking to Vogue in 2020, Nicks said of Styles: "He's the type of person you'd wanna live next door to. He'd look out the window, see you having a hard time planting flowers, and rush out asking, 'Can I help you with those roses?' 'Sure, but you are Harry Styles, right?' That's who he is."
Read more about their friendship here.