The 30-year-old has reportedly been put into a medically induced coma and remains on life support after suffering an alleged overdose on Friday, according to various reports.
Per the Daily Mail, Fielder-Civil, who's had a long history of substance abuse, was found by his partner, Sarah Aspin, choking in bed Friday and was rushed to a nearby hospital in West Yorkshire, England.
He reportedly suffered multiple organ failure and has been placed on life support.
According to The Sun, Aspin claims that Fielder-Civil arrived home on Thursday "slurring his words and staggering," and she feared that "he was on something." The couple has a 15-month-old son together.
On Thursday, Fielder-Civil's friend Yeya Jáuregui tweeted an update about his condition, which was provided by his mother, Georgette Civil, on Facebook:
"She said: 'thank you [for] all for your prayers and good thoughts. His kidneys are not working well and he has a regular cough. Blake [has] a lung infection and has not awakened yet.'"
Fielder-Civil and Winehouse, who were married for two years until 2009, had an infamously tempestuous relationship punctuated by reports of rampant substance abuse and violent fights. In 2011, he was incarcerated for burglary and firearm possession.
Amy's father, Mitch Winehouse, took to Twitter Thursday to express his concern over Fielder-Civil's health, writing, "Terrible news about Blake this morning. Remember Amy loved him. Let's pray for his recovery."
(Originally published on Aug. 9, 2012 at 5:18 a.m. PT)