The "Showgirls" star had just taken up boxing training for 1996 mob movie "Bound" when she found herself matched up with Dylan as sparring partners.
But their first round in the ring ended with a powerful punch to Dylan's jaw, and although Gershon was "mortified" by her flying fist, the singer simply laughed off the mishap.
"I met him and I punched him in the face, that's an honest beginning...," Gershon said on the podcast "Life Is Short with Justin Long".
"We were sparring and I hit him in the face. I hit him so hard and I just started laughing. I mean, I started crying (first) and he started laughing. (He said), 'I need a good woman to kick my a** every now and then,' and I was mortified! I'd never even hit someone before! After I hit him, I never wanted to spar again, 'cause I'm like, 'How do you kind of hit someone?' I don't wanna be hit!".
Blaming her tendency to fight back when under attack on her childhood experience of life with a big brother, she explained, "If someone comes after me, I just go like, 'Arghhhhh!' and so when Bob just very lightly tapped me, I just went, 'Bam!' I went crazy and I smashed him."
Despite the rocky start to their relationship, Gershon and Dylan became good pals, and the legendary musician is the person she now turns to whenever she's feeling a little out of sorts.
"He's great, I love him," the actress gushed. "He's become a person who, if I'm on tour or if I've been on the road, doing something, if I've been in different places, when I feel weirdly not lost, but out of sync, I tend to call him...".
Dylan, 78, helped to pull Gershon out of a recent funk by inviting her to hang out at his Los Angeles recording studio, where they just talked for hours.
"He's just one of these guys, we just talk and talk, and I swear to God, I don't know remember half the stuff we talk about," she laughed. "We just get into the ethers, but we just don't bulls**t about things."
And Gershon, 57, was given a little preview of some new material Dylan had been working on: "He read me some lyrics he was writing and he was all excited...," she recalled. "I was thinking, 'Oh my God, this is so cool.' You could see why he still loves doing what he does and he's excited..."
"I never think about it (his level of fame) when I'm with him, like, 'Oh, he's Bob Dylan,' and I think that's what he likes about it."