The husband of Extras actress Ashley Jensen took his own life at their Somerset home, an inquest has heard.
Emergency services were called to actor Terence Beesley's home in Camerton, near Bath, on the afternoon of 30 November last year.
Avon Coroner's Court heard the 60-year-old was found in a car in his garage.
Coroner Peter Harrowing concluded that his death had been as a result of suicide. The medical cause of death was carbon monoxide toxicity.
In a statement read out at the hearing, Jensen - whose name was given as Ashley Beesley - said she had been "extremely shocked" by what happened.
The actress had called the emergency services after coming home and finding her husband.
Paramedics tried to revive Beesley, who played Buxton in ITV's Victoria and General Bennigsen in BBC One's War and Peace, but he was pronounced dead at the scene, the coroner's court heard.
Jensen said in her statement that she had last spoken to him via text and email on the afternoon of his death.
She said: "I was extremely shocked by what happened that night and I will never forget it.
"Terry and I had been together for 18 years but I had no idea he was capable of what he did."
Dr Sam Robinson, her husband's GP, said in a statement that the actor had "no past medical history of any mental health issues".
Mr Harrowing said: "There is no evidence that I have heard to indicate why Mr Beesley took the act that he did but in any event it is not my function to answer the question why Mr Beesley might have taken that act.
"Mr Beesley knew that his wife and young child were not at the house and he would not be disturbed... I am satisfied beyond reasonable doubt that Mr Beesley made a deliberate act."
In her statement, Jensen - who also starred in US show Ugly Betty - said she first met her husband in 1999 when they both performed in a production of King Lear.
They married in 2007 and their son was born two years later.
Jensen said that her husband was outgoing and had many friends and colleagues.