Lil Wayne had run through a string of hits during the taping of his “MTV Unplugged” special Thursday night before he took on a rather serious tone.

“A few months ago I was in a dark place that I don’t like to really shed light on,” he said referring to his time behind bars last year. “Everyone always asks, ‘How was it?’ I figured I’d find a way to answer that question.”

The rapper then launched into a cover of 2Pac’s “Hail Mary” –- the last single from his final studio album, “The Don Killuminati: The 7 Day Theory.”

Wayne was incarcerated for attempted gun possession, from a 2007 arrest following a Manhattan concert.

During his time behind bars — which included a month of solitary confinement as punishment for possessing “music contraband” (headphones and a charger for an MP3 player) — he released his last disc, “I Am Not a Human Being,” and it debuted at No. 2 on the Billboard 200 chart, with 110,000 downloads in its first week.

With lyrics like

 “penitentiaries is packed with promise makers … institutionalized I lived my life a product made to crumble,”

Wayne said he dug around for the perfect song to describe how he felt during the eight months he spent at Rikers Island.

He’s aware going forward that people are going to continue to ask, and he said he’ll do more than offer the 2Pac classic — he previously spoke about his experiences for Rolling Stone’s February issue.

“I think I’m going to have to open up more because of this social world we live in now,” he said backstage after the taping. “People are going to think I’m an alien if I don’t say anything about it. You know this world we live in now you can find out anything about everybody.”

During the concert he also treated the hundreds of fans who packed a soundstage at Sony Studios to a track off his highly anticipated disc, “Tha Carter IV,” with a performance of “Nightmares of the Bottom,” where he reflected on his troubles — with a bit of humor.

“If I knew I was going to jail I would have … my attorney,”

He rapped.

He’s tight-lipped about the disc, which was pushed back to a June 21 release, but did offer a cryptic teaser when asked about it.

“Just know that I have a pleasant surprise. A very pleasant surprise for this album when it comes out,” he said. “I’m only doing this for the fans. Which I do every … thing for.”

Wayne joins a small roster of hip-hop acts to have gotten the “Unplugged” treatment, including LL Cool J, Jay-Z, Lauryn Hill and B.o.B.

“It was humbling just to be a part of. As an artist that’s watched the game as closely as I did, to be on ‘Unplugged’ is a high honor,” Wayne said. “I’ve gotten people that haven’t texted me in a long time, text me today saying congratulations. It is that kind of thing. I felt great about it.”

“MTV2 Presents: Lil Wayne Unplugged” will premiere on June 12 on MTV and online at 9 p.m.