The gang has been on a lot of adventures and undergone a lot of change in the past seven seasons of It's Always Sunny in Philadelphia. They've run for political office, bought a boat and even broken the Liberty Bell. And in last night's episode, they solved the city’s trash crisis and looked back at the many insane plans they've left in their rearview mirror.

However, Season 8 isn’t going to be all about nostalgia. Spinoff Online caught up with star and writer Charlie Day in a recent phone conversation to discuss the new season, which includes next week’s episode revolving around “Maureen Ponderosa’s Wedding Massacre,” and a guest role for his Pacific Rim director Guillermo del Toro. And if that wasn’t enough to look forward to, day teased that Charlie and the Waitress might finally have a real love story.

Spinoff Online: Last night's episode, "The Gang Recycles Their Trash," was definitely a throwback to earlier seasons. Why did you decide that now is the right time to walk down memory lane?

Charlie Day: Actually, we were just breaking the "Trash" episode the way we break any other episode because we always thought the idea of a trash strike -- I mean, historically there's been some in Philadelphia -- so we thought the idea of a trash strike would be good subject matter for a classic Sunny episode. As we were breaking the story we were saying it feels similar to the gas crisis episode and we were just kind of amused by the fact that these characters never really attempt to bring up any of their own plans, and they have a million of them.

They come up with an idea and they throw it away just as easily, and we though, given the climate of garbage and filth, that the concept of, "Hey, maybe we shouldn't always be throwing our ideas away" could be a funny subject matter for the characters, more to do with that than any sort of meta kind of storytelling. It really is a certain matter of these characters saying, "Hey, why do we always drop things and never bring them back and maybe we should attempt to reexamine our process and try out the things we tried in the past, and then they overlap with things that they've done and then we have all the callbacks, and it was fun to do an episode like that.

As someone who has been watching Sunny for years and years, it really did feel in that episode like these characters have grown. I know that's something showrunner Rob McElhenney has said in the past was important to him and that's why he gained all the weight as Mac last season, so is that a change we'll continue to see going forward?

Well, you know, I do think they grow, but they grow in the way a criminal grows. They don't necessarily learn their lesson and decide that everything they did was wrong and have some sort of come-to-Jesus moment. They get sharper in their crimes and darker in their [laughs] their mischievousness and evolution by de-evolution. I think they're always changing, but something at their core stays the same.

I will say, a "The Gang Finds Jesus" episode would be fantastic.

It would be good, it would be good.

In the synopsis for Season 8 on the Sunny website it says that Charlie finds love this season. Is it too much to hope that it will be with The Waitress?

It's not too much to hope. It's a really fun episode because the Waitress is involved but a new woman is also involved, and it will be interesting to see which direction the fans actually want the character of Charlie to go.

I had the pleasure of catching up with Mary Elizabeth Ellis at the Sunny premiere red carpet and she said the Waitress has become a lot like Charlie this season. Will that element come into play in the storyline?

That is one way that I think people can read into it. I think in that scene you will see maybe an evolution certainly in their relationship and the way that it's approached. The episode deals a little bit more with -- and I think the audience will respond to -- a deeper understanding of what the connection is that these two people have, whether positive or negative, and the way in which they've been co-existing for the past 10 years. I think we'll find romance in this episode is very dark and confusing way, but we'll still be able to find some romantic moments out of those twisted approaches to it insofar that I think it's [an episode] that does break a little new ground for Sunny or at least achieves what we do best when we do hit those tones.

I'm excited to see it. Mary Elizabeth also teased that episode 3, "Maureen Ponderosa's Wedding Massacre," is her favorite this season. Can you talk a little bit about that?

Absolutely. It's definitely one of my favorites that I've ever written, and I think it's stylistically one of our best with some slightly different camera stuff in this episode that is different than your average episode of Sunny but still seems to fit into what this show is and the history of this show, and it still will feel very much like a Sunny episode. I think that's one that the fans are really going to enjoy.

I guess the joke is sort of in the title of that episode, but will it specifically tie into Halloween? Is it going to be themed, since the holiday is the next week?

It's not directly going to tie into Halloween. It does take place on a Friday the 13th, so the aspect of it will be spookiness, bloodiness, the darker tone of the episode.

I was on a conference call with Rob and Glenn [Howerton] recently and they said that Guillermo del Toro is going to have a cameo appearance this season. I'm assuming that that ties back to you, so can you explain the backstory of how that idea came about?

Guillermo is a big Sunny fan and it's why he offered me the part in Pacific Rim and, when I went to meet with him, he said, "Oh, I want you to be in my movie and in return I'd love to be on Sunny." We joked about it the whole time we were filming because he was beating me up pretty bad day after day and he said, "Oh, I can't wait to see what you're going to do to me," but I never knew whether he was totally serious and really wanted to do an episode, or whether that was his way of joking around.

So when we wrapped the movie and then wrote the season, I sent him an email and said, "All right, we've got a part for you," and he jumped on the opportunity and he even did a little bit of his own make-up in terms of he had a wandering eye, a glass eye, made for the part, which is great. And he's fantastic, actually. His performance is really good, too, and he had a special line he wanted to say, and we loved it and we kept it and so he was a really great contribution. It's that episode, too. It's the "Wedding Massacre" episode.

Is he playing himself or a character?

He's not playing himself. I can't say the name of the character because it's going to give away a twist in the episode, but he's playing a relative of some characters that we know.

I'm really excited to see it, both as a fan of you guys but also of him.

I think, on both projects, people will be pleased.

It’s Always Sunny in Philadelphia airs Thursdays at 10 ET/PT on FX.