The 61-year-old died 10 years after their relationship began in 2014.
Carmel-by-the-Sea, a tiny town in California with just over 3,000 residents, was Sandera’s home.
While the two did not meet while he was in office, he did contribute to the building of a library annex, as well as the installation of public facilities, beach pathways, and a tourist parking lot.
No, it is believed that Sandera’s job as a host at the town’s Mission Ranch Hotel and Restaurant is where the pair first met.
Eastwood bought the estate after saving it from developers and restoring it to provide a one-of-a-kind resort experience.
Sandera and her 94-year-old partner kept a quiet profile, despite attending several red carpet events.
One of these was the 2015 Academy Awards, where Eastwood received six nominations for his part in directing the hit film American Sniper.
Eastwood released a statement Thursday night, according to the Hollywood Reporter, although the cause of her death remains unknown.
His statement said, “Christina was a lovely, caring woman, and I will miss her very much.”
Meanwhile, a Warner Bros. official told the outlet that there would be no further details disclosed concerning her death.
In addition to the Academy Awards, she was by Eastwood’s side for other premieres, including Sully in 2016, which he directed, and The Mule two years later, in which the award-winning actor appeared and directed.
Sandera also appeared among the stars at the Eastwood-directed premieres of The 15:17 to Paris in the same year and Richard Jewell in 2019.
Although the pair never had children together, Eastwood is the father of eight children by six other women with whom he has been in relationships.
He has two boys, Kyle and Scott, and four daughters: Alison, Francesca, Kimber, Laurie, and Morgan.
Before dating Sandera, Eastwood had two marriages. He married model Maggie Johnson in 1953, but they separated in 1964 and divorced 20 years later.
And in 1996, he married Dina Ruiz, a TV newswoman, before divorcing her in 2014.
Eastwood is now working on his 40th picture as a filmmaker, Juror No. 2, which is currently in postproduction.