A statement posted to Harris' Facebook page noted that Harris -- whose motorcycle crashed on set, according to police -- was "the first African-American female road racer."
"We are deeply saddened and heartbroken by the loss of Joi 'SJ' Harris. Joi was an extraordinary woman with a passion for riding and motorsports. She was known for her beautiful spirit and bubbly personality. She was fearless and relentless in her pursuit of her dream, to ride as a motorsports professional," the statement read.
"She was living her dream, when her life was suddenly cut short while filming as a stunt rider. She will be dearly missed by her race fans all over the world. We ask that you respect the privacy of her family and friends, as we mourn her loss."
"We're heartbroken, shocked and devastated... but recognize nothing can come close to the grief and inexplicable pain her family and loved ones must feel in this moment," Reynolds tweeted. "My heart pours out to them -- along with each and every person she touched in this world."
20th Century Fox did not have a new statement when contacted by ABC News Tuesday.
"Deadpool 2" is slated for a 2018 release.