Ashton Kutcher has resigned from his anti-child sex abuse charity following outrage over a letter of support to a judge after Danny Masterson's rape conviction.
In his resignation to the charity, Thorn, Kutcher says his support letter was an "error in judgement".
Masterson was sentenced to 30 years to life in prison for the rape of two women.
A similar letter was sent by Kutcher's wife, actress Mila Kunis.
The letters and subsequent apology from Kutcher and Kunis - both of whom starred in That 70s Show alongside Masterson - were widely criticised by victims and advocacy groups.
In a resignation letter directed to the board of Thorn and posted online, Kutcher says his decision to step down from the board is rooted in the recognition of recent events.
He says after his wife and he spent several days of listening, personal reflection, learning and conversations with survivors and the employees and leadership at Thorn, he has determined the responsible thing for him to do is resign as chairman of the board, effective immediately
Kutcher says he cannot allow his error in judgment to distract from their efforts and the children they serve.
Established by Kutcher and ex-wife Demi Moore in 2012, Thorn focuses on combatting sexual exploitation of children.
In his resignation message, Kutcher says his letter of support for Masterson - in which he described him as someone who treated people with "decency" and "generosity" - was "yet another painful instance of questioning victims who are brave enough to share their experiences".
He adds this is precisely what they have all worked to reverse over the last decade.
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