Ashton Kutcher and Mila Kunis wrote reference letters of support on behalf of Danny Masterson before he was sentenced on Thursday to 30 years to life in prison.

Kutcher and Kunis, who co-starred with Masterson in "That '70s Show," are married. In their letters, first published by Los Angeles court reporter Meghann Cuniff and journalist Tony Ortega, the couple vouched for Masterson's character and pleaded with Judge Charlaine Olmedo for leniency.

Kunis and Kutcher were among nearly 50 individuals to submit letters in support of Masterson. The actor was convicted in May on two counts of rape.

"While I'm aware that the judgement has been cast as guilty on two counts of rape by force and the victims have a great desire for justice. I hope that my testament to his character is taken into consideration in sentencing," Kutcher wrote. "I do not believe he is an ongoing harm to society."

"I wholeheartedly vouch for Danny Masterson's exceptional character and the tremendous positive influence he has had on me and the people around him. His dedication to leading a drug-free life and the genuine care he extends to others make him an outstanding role model and friend, Kunis wrote.

"From the very beginning, I could sense his innate goodness and genuine nature," she added of Masterson in her letter. "His caring nature and ability to offer guidance have been instrumental in my growth both personally and professionally."

CNN has reached out to representatives for Kunis and Kutcher for comment.

Masterson has maintained his innocence and plans to appeal his conviction.