Siblings Cody and Caleb Walker are acting as stand-ins and body-doubles for scenes featuring their brother, who died in a November car crash at the age of 40.
"Having them on set has made us all feel that Paul is with us too," read a statement posted to the film's official Facebook page last week.
Production on the seventh installment in the "Fast" franchise was temporarily halted following Walker's death, but has since resumed in the United Arab Emirates.
On Monday, a photo was posted on the film's official Instagram page showing the brothers having a chat with actor Vin Diesel:
Walker had portrayed former FBI agent Brian O'Conner in five of the six previous films in the franchise. Producers have said that the character will be "retired" after the seventh film.
"Fast & Furious 7" opens in theaters on April 10, 2015.