April 25 (UPI) -- Demian Bichir is mourning the death of his wife, actress Stefanie Sherk.
The 55-year-old actor announced in an Instagram post Tuesday Sherk died April 20 at age 37.
"Dear friends, On behalf of the Sherk and the Bichir Nájera families, it is with inconceivable pain that I announce on April 20, 2019, our dearest Stefanie Sherk, my beloved and loving wife, passed away peacefully," Bichir captioned a photo of the actress.
"It has been the saddest and toughest time of our lives and we don't know how much time it will take for us to overcome this pain. Stefanie's beautiful, angelical and talented presence will be immensely missed. We will hold Stefanie in our hearts forever.
Bichir thanked fans in advance for their support but asked for privacy as he grieves.
"We thank everybody beforehand for their prayers and we respectfully ask for your understanding so we may grieve in peace and privacy in these incredibly difficult times," he wrote. "It is our sincerest hope that our beautiful Stefanie, my angel and love of my life, will rest in eternal peace."
The Weeds and The Bridge alum did not elaborate on Sherk's cause of death.
E! News said Bichir and Sherk have been together since 2010. The couple co-starred in the 2016 film Un Cuento de Circo & A Love Song, which Bichir also directed.
Bichir and Sherk attended the Los Angeles premiere of Bichir's film The Nun in September. Bichir shared a photo from the event at the time, writing, "Complete. Yet one more happy day with his beautiful woman."
Bichir is known for playing Esteban Carlos Reyes on Weeds and Det. Marco Ruiz on The Bridge. Sherk portrayed Marlee's mom on #Hashtag: The Series and appeared on The Bridge and CSI: Cyber.