The Harry Potter star stated that he feels no rivalry with The Twilight Saga star, who appeared alongside Grint in Harry Potter and the Goblet of Fire.
"There's no rivalry," Grint said in an interview with Attitude Magazine. "It's great to see Robert in this huge thing. I was pleased for him."
Grint went on to open up about the final day of shooting the last instalment in the Harry Potter movies, claiming that he found it to be very emotional.
"We had a barbecue," Grint said. "I brought my ice-cream van. They had a mariachi band. It really was quite emotional, surprisingly."
Grint's co-star Emma Watson recently revealed that she was more nervous about kissing Grint than she was about kissing Daniel Radcliffe in the Harry Potter films.
Tom Felton, who plays Draco Malfoy, confessed last week that the Harry Potter cast feared being replaced, stating that he is proud to have made it through all eight movies.
Harry Potter and the Deathly Hallows: Part 2 opens in cinemas on July 15.
Watch a trailer for Harry Potter and the Deathly Hallows: Part 2 below: