Rosie O'Donnell is mourning the loss of her father, Edward Joseph O'Donnell, who died at 81 after battling cancer.

He worked as an electrical engineer in the defense industry, Us Weekly reported.

During an interview with CNN's Piers Morgan in 2012, the 53-year-old comedienne admitted to having a strained relationship with her father.

"He had his own issues and demons, he had a very tough childhood, he had an alcoholic, abusive father and never really got the help that I think every person needs when they have lived through that as a child," O'Donnell said. "I think that he had a lot of problems to deal with. You get to be 50 years old you can't still be angry at what your father did in 1970. You have to work it out for yourself and find a place for it in your life and not rehash it forever."

The news comes a week after the former "View" co-host's 17-year-old daughter, Chelsea, went missing for seven days in New York City. She was later found alive in a friend's New Jersey home with an alleged drug addict she met on Tinder.

Steven M. Sheerer was arrested on Friday and charged with child endangerment and communication of obscenity in connection with Chelsea's disappearance. After searching Chelsea's phone, police reportedly found "evidence of inappropriate communications over the last several weeks between Sheerer and the minor."

Sheerer, who is a convicted drug offender, was being held in an Orange County jail on $40,000 bail and if convicted could face up to 10 years in prison on both charges.

Us Weekly reported that Edward Joseph O'Donnell is survived by Rosie, her four siblings and his grandchildren.