Our North Korean government minders informed us Monday night that we'd be interviewing Joo, a request we made on Saturday, just hours after arriving in the country.
CNN was given exclusive access to the South Korean citizen, who is a permanent resident of the United States and has been detained in North Korea since last month.
Joo was most recently living in New Jersey and studying at New York University. He took a semester off to travel across the United States and says he went to North Korea after an unsuccessful attempt to find work in California.
Joo didn't seem alarmed that he could be facing serious charges and prison time for illegally entering North Korea through China.
"I'm willing to accept any punishment," Joo says.
Over barbed wire, through farmland
Joo says he crossed into North Korea near the Great Wall of China in Dandong, an area near the border that offers views of the reclusive nation, which tightly controls access for foreign visitors.
He says he crossed two barbed wire fences and walked through farmland until he reached a large river. He says he followed the river until soldiers arrested him.
"I wanted to be arrested," he says.
North Korea calls itself the DPRK, or Democratic People's Republic of Korea.
"I thought that by my entrance to the DPRK, illegally I acknowledge, I thought that some great event could happen and hopefully that event could have a good effect on the relations between the north and [South Korea]," Joo says.
Joo says he wasn't sure what kind of great event could happen due to his actions.
"I hope that I will be able to tell the world how an ordinary college student entered the DPRK illegally but however with the generous treatment of the DPRK that I will be able to return home safely," he says.
Joo says it was, in part, curiosity that led him to North Korea. He said he'd been thinking about making the trip since February.
"Once the thought of entering the DPRK seeped into my mind, I couldn't really escape it. I guess I constantly thought about it," he says. "I thought that as an American permanent resident and South Korean citizen that my entrance could have some good effect."
First message to world
Joo was born in Seoul, South Korea and moved to Wisconsin with his family in 2001. He says he later moved to Rhode Island.
He says he has not spoken to his parents or any representatives of the United States or South Korean governments.
His interview with CNN is his first opportunity to send any kind of message to outside world.
"Of course I understand my parents and my loved ones are worrying a lot about me. But I would like to say that I'm well and there's no need to worry because the people here have treated me with the best of humanitarian treatment," he says.
Joo says he's healthy and well fed. His room has three beds and a private bathroom. He has no access to television, radio, or the Internet. He has not been able to make phone calls.
"I understand that I cannot make outside contact because I did enter the country illegally," he says. "I did commit a wrong act so I understand that I cannot freely move around because I'm currently a criminal."
Joo says he has not been informed if he'll face charges or when he will allowed contact with his family or the outside world.
Arrested in April
North Korean state media reported Joo's arrest on Saturday, more than one week after his arrest on April 22.
The North Korean Central News Agency said the student had illegally crossed into North Korea from China, via the Yalu River, and had "admitted that his illegal entry was a serious violation" of North Korean law.
In a regular press briefing on Monday, South Korea's Unification Ministry spokesman said it was "extremely regrettable" that North Korea had detained Joo without notifying his family or South Korean authorities.
"Our government strongly urges North Korea to repatriate student Joo to his family as soon as possible," said spokesman Lim Byeong-cheol.
On Sunday, CNN interviewed two other South Koreans
being held by North Korea, who has accused them of being "spies."
In separate interviews, with North Korean minders present, the two South Korean men -- Kim Kuk-gi and Choe Chun-gil -- said they admitted the allegations against them.
South Korea has also called for their release. In March, the South Korean National Intelligence Service denied the men had been working for the agency.