Former Home and Away actress Jodi Gordon, ex-Neighbours star Stephen Curry and castmates Daniel MacPherson and Shaun Micallef walked the red carpet with jockey Damien Oliver, who Curry plays in the film.
The Cup tells the story of Oliver's victory in the 2002 Melbourne Cup on horse Media Puzzle just days after his brother Jason died in a trackwork accident.
Damien, who attended the screening with wife Trish and their three children, told the Herald Sun: "It feels really weird to see part of your life in a film, but it has been a long time coming and we are really excited.
"They have done a wonderful job and we feel honoured to have a film made about this piece of our life."
Damien admitted that the film brought back painful memories of his brother's death and the turmoil he felt while deciding whether to take part in the Melbourne Cup that year.
"At the time I was really torn apart as to whether I should ride," he said. "It really came back to what my brother would have wanted. If I had not been there with that horse and been sitting home watching it, he would have been really upset with me."
Trish also revealed that she was very happy with the way Jodi Gordon portrayed her in the film, saying: "She is such a beautiful girl. I was honoured to meet her and I loved the way she played the role on screen."
Earlier this year, Curry admitted that he struggled with the horses on the set of The Cup, saying: "The horses and I don't really get along. They are wonderful, beautiful creatures, but so are great white sharks.
"I don't want to swim with them or be on them, I just want to bet on them. We had 500 extras on day one and I got bucked off in front of all of them."
Watch the cast of The Cup on the red carpet at the premiere below: