Image copyright Stephens County Jail Image caption The mother and daughter married in 2016

An Oklahoma mother who married her daughter after the pair "hit it off" has been sentenced to two years in prison.

Patricia Ann Spann, 45, pleaded guilty to the felony offence of incest and admitted wedding her biological daughter, Misty Velvet Dawn Spann, 26.

The mother lost custody of her children and reunited with her daughter in 2014.

The two married in March 2016 after same-sex marriage became legal in the state.

Investigators later discovered Patricia Ann Spann had previously wed her son.

Her son, who was 18 years old at the time, annulled the marriage on incest charges in 2010 after tying the knot with his mother in 2008, according to the Oklahoman.

The married mother and daughter were discovered by the Department of Human Services during a child welfare check-up.

According to the Oklahoman, Misty Spann also had the marriage annulled in October last year after arguing she had been fraudulently induced into it.

She said her mother had lied about consulting "three separate attorneys who advised there would be no problems with the marriage", reports the newspaper.

Patricia Ann Spann said she believed the union was legal, since she was not listed as the biological mother on her daughter's birth certificate and had only come into contact with her two years ago beforehand.

Misty Spann pleaded guilty to incest last November and was given 10 years of probation and required to undergo counselling.

In addition to her prison term handed down on Tuesday, Patricia Spann will serve eight years of probation and must register as a sex offender upon release.

Under state law, marriage to a close relative is considered incest, regardless of whether a sexual relationship exists.