Former Hillsong pastor Carl Lentz in outpatient treatment for mental illness

Carl Lentz is seeking help. The former Hillsong pastor is undergoing mental health treatment after he was asked to step down from leadership at the Christian megachurch in November for "moral failings."

A source tells ET that Lentz will be actively seeking treatment at an outpatient facility that specializes in depression, anxiety, and pastoral burnout.

The source says Lenz is seeking treatment in an effort to improve himself for his family, and he is dedicated to getting the help he needs as his family supports him.

The pastor -- who was once very close with Justin Bieber and acted as a spiritual adviser to the singer -- was a leader at Hillsong for over 10 years before the church asked him to step down in November.

Lentz later addressed his departure in a lengthy Instagram post in which he admitted that he had cheated on his wife of 17 years, Laura.

"I was unfaithful in my marriage, the most important relationship in my life and held accountable for that. This failure is on me, and me alone and I take full responsibility for my actions," he captioned a photo of himself with Laura and their three children. "I now begin a journey of rebuilding trust with my wife, Laura and my children and taking real time to work on and heal my own life and seek out the help that I need."

Lentz also shared a message for the church congregation, apologizing for his actions.

"I am deeply sorry for breaking the trust of many people who we have loved serving and understand that this news can be very hard and confusing for people to hear and process," he wrote. "I would have liked to say this with my voice, to you, in person because you are owed that. But that opportunity I will not have. So to those people, I pray you can forgive me and that over time I can live a life where trust is earned again."

Hillsong Church later announced in a statement that it was appointing an outside law firm to investigate concerns after the leadership change.

"Since last week’s announcement of a leadership change at Hillsong East Coast, we have heard from a number of people about their experiences and concerns," the statement reads. "It is important that we establish the truth and then do everything we can to ensure our church is both a safe place and one that seeks to glorify God in all that we say and do."

"For this reason we have decided to appoint a New York based legal firm that is not associated or affiliated with Hillsong to conduct an in-depth review and investigation into all concerns and any wider cultural issues," the statement continues. "We are taking this extremely seriously and on the basis of this report, we will be better positioned to take whatever actions are deemed necessary to right the wrongs and see Hillsong East Coast move forward in a way that enables many more people to find hope in Jesus."

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