New Jersey Congressman Tom Kean Jr. has revealed the reason behind his lengthy absence that kept him out of public view for nearly four months.

“I am a private person by nature … talking about myself has never come naturally. But I believe that I owe an explanation to the people of New Jersey’s 7th District, to my colleagues in this chamber and to the American people for my absence,” he began from the podium Tuesday morning.

“Several months ago due to health concerns, I entered the hospital for some testing. I did not believe that this would result in a long-term stay. I was given the diagnosis of depression,” Kean, 57, said in the extraordinary speech on the House floor.

“Now when people hear the word depression, many people think, simply feel, it means feeling sad. But depression is so much more than that. It is physical, it is emotional, and until you experience it yourself, it is difficult to fully understand how powerful this illness can be.”

Despite feeling hesitant, Kean said he stayed in the hospital at the recommendation of his doctors, a decision he came to be grateful for.

“I began to understand not only my diagnosis, but how long depression had been affecting my life,” he said.

“When I first informed the public that I was dealing with a medical issue, I was still trying to understand what was happening myself,” he said of the shroud of secrecy behind his absence.

“When I said I hope to return in a matter of weeks, I believed it. Those were the best estimates that the doctor could provide. But as the over 48 million of my fellow Americans being treated for this illness have come to discover, there is no timeline for healing. There is no timeline for recovery. Only the work of getting better one day at a time,” he said.

“Today I am grateful that I listened to my doctors … I am grateful that I accepted help. Because today I stand before you healthier, stronger and excited to return to the work that I love.”

Kean returned to his Westfield home Wednesday evening but declined to speak to a New York Times reporter, saying, “It’s good to see you. I’ll talk to you next week.”

The Republican’s spokesman, Harrison Neely, told the outlet in a subsequent text message that Kean would be “fully transparent” when he returned to work June 30.

Rumors swirled in Kean’s absence as his team wouldn’t comment on his disappearance beyond calling it a “personal health matter” and claiming the congressman was “focused on his recovery.”

Although the public had no information about his condition, the details were apparently known by Capitol Hill colleagues including House Speaker Mike Johnson (R-La.), who earlier this month would only say, “I do know what his health issue is, but he’s asked me not to disclose that, and I’m going to honor that.”

Follow The Post’s live coverage of President Trump and national politics for the latest news and analysis

He assured “it’s not a scandalous thing at all,” and reminded reporters that “people deal with health issues. Maybe that’s a news flash for you, but even members of Congress get sick as well.”

Kean hasn’t cast a House vote since March 5, missing more than 140 roll calls since. Some constituents had complained their calls or emails had gone unanswered.

His chief of staff, Dan Scharfenberger, inadvertently compounded the mystery May 12 with a cryptic explanation to the Times, “There’s no cameras where Tom is.”

During his absense, Kean won the Republican nomination for a third House term repping New Jersey’s 7th Congressional District after running in the primary unopposed.

He will face Democrat Rebecca Bennett in a race seen by many as a toss-up.

If you are struggling with suicidal thoughts or are experiencing a mental health crisis and live in New York City, you can call 1-888-NYC-WELL for free and confidential crisis counseling. If you live outside the five boroughs, you can dial the 24/7 National Suicide Prevention hotline at 988 or go to SuicidePreventionLifeline.org.