On December 10, 2018, Clint Eastwood was photographed at the movie's Los Angeles premiere with his secret daughter Laurie. She identified herself to photographers as 'Laurie Eastwood'. The next day, Alison Eastwood confirmed on Instagram that Laurie is her half-sister. Laurie is believed to be the Washington-born Eastwood daughter who was given up for adoption in 1954, as alleged by biographer Patrick McGilligan in the heavily suppressed book "Clint: The Life and Legend" (1999) - an allegation no media outlet would repeat at the time. It has taken Clint 64 years to acknowledge Laurie.
The release of The 15:17 to Paris (2018) and this movie mark the eighth time Clint Eastwood directed two features for release in a single year. The other years were 1973, 1982, 1990, 1997, 2006, 2008 and 2014.
Yves Bélanger's inclusion as cinematographer marked the first time Clint Eastwood did not work with Tom Stern as his cinematographer on a feature film in eighteen years. Stern worked as a gaffer on several of Eastwood's films from the 1980s into the early 2000s, before being promoted to director of photography on every scripted feature-length film by Eastwood, starting with Blood Work (2002) (Stern's first cinematography credit) to The 15:17 to Paris (2018) (Eastwood's earlier 2018 film).
One of Earl's (Clint Eastwood's) handlers scolds him for speaking without being asked, by saying, "Mules don't talk!". Clint Eastwood's first credited movie role was that of "Jonesey", in Francis in the Navy (1955), which was part of the "Francis, The Talking Mule" series.
The trivia item below may give away important plot points.
Clint Eastwood's character Earl Stone drives thru a fast food restaurant named "Gunny's Burgers". Clint Eastwood played the role of Gunnery Sgt. Thomas Highway nicknamed "Gunny" in Heartbreak Ridge (1986), which Eastwood also directed.