It’s been almost a year since Gregg Gillis, aka mash-up artist Girl Talk, co-headlined the 80/35 Music Festival, and Monday he makes a return visit to the Val Air Ballroom.

So what’s he been up to since we saw him last?

“I’m working on a bunch of new stuff,” Gillis said during a phone interview. “I’m branching out for the first time in years with some material that’s not intended for shows. It’s outside the box of the last two records.”

That “box” is the trademark Girl Talk style of mashing up hip-hop lyrics over radio- friendly hits, or vice versa. Gillis said the music will still be sample based, but using more obscure source material or cutting up the songs more so they’re not as instantly recognizable. He said there will even be original instrumentation involved.

Monday’s show at the Val Air Ballroom puts Gillis into a more familiar atmosphere for a Girl Talk show: Indoors. He’s done more and more festival gigs over the years, but in his heart he loves the feel of a club show.

“I do enjoy outdoor festivals, but the indoor shows have a slight advantage: it’s easier to control that environment,” Gillis said. “There’s more control over the lights and what’s going on, and people can lose themselves a little more in a confined space. They feel more protected and hidden.

“I’ve noticed in the clubs it’s more of a free-for-all. The indoor shows always feel closer to what the show evolved out of and what it used to be. It’s more intense, typically.”

While he hasn’t released a new album since 2010’s “All Day,” Gillis is constantly mixing new material into his live show. He said at this point his show is about half material that isn’t on any record, though the live shows aren’t yet featuring the outside-the-box material he’s been working on. Gillis said how a live audience reacts lets him evaluate how well the music is working.

“Fans will naturally react in a live setting,” Gillis said. “When you’re trying out something new, it has the potential to fall flat. When it does translate that’s a great feeling, but if they don’t react it doesn’t automatically signal to me that I need to get rid of it. It may not be working now, but if I still think it’s musically interesting I may hold onto it. Sometimes it takes getting on an album first to get people into it.”

Gillis said he currently has enough material for a more traditional album, following in the footsteps of “All Day” and “Feed the Animals,” but he’s not sure whether that or the “outsider” material will get released first. Whichever is the case, he said he would like to have one of the new albums out within a year.

“I’m excited about taking some sharp turns. I don’t like making decisions by thinking ‘What will sustain this as a career?’ I’m excited to be doing something a bit weirder.”

Girl Talk

Girl Talk

When: 7 p.m. Monday

Where: Val Air Ballroom, 301 Ashworth Road, West Des Moines.

Cost: $25 in advance, $30 day of show.

Tickets: Ticketmaster