If you have yet to see last week's season opener of the FX comedy "It's Always Sunny In Philadelphia" you missed, among other things, the fifty-pound weight gain of Mac (series creator Rob McElhenney), a blood spewing mishap in a limousine involving Frank (Danny DeVito), Charlie (Charlie Day) and a woman they found on a millionaire dating website, Sweet Dee (Kaitlin Olson) discovering she can use her feet to make cash and the death of a prostitute that Frank, in a twisted homage to the film "Pretty Woman," decided he wanted to marry. As more of the seventh season unfolds tonight, the gang takes a trip to the Jersey Shore with certain characters having a joyously, wonderful time and others having the complete opposite experience.

Our Jim Halterman recently rang up McElhenney to talk about constructing the hilarious stories seen on the show, the silver lining to gaining all the weight (and what he's doing to lose it) and whether we'll see a musical-themed episode a la season four's 'The Nightman Cometh' episode (which the cast also performed live in six cities in 2009).

Jim Halterman: The episodes of "Sunny" veer off into some really unexpected, surprising places which makes me wonder how exactly you and your writers break the stories we see. Can you walk me through that?

Rob McElhenney: Ultimately, the writing process is very different from episode to episode but it will start on the first day when all the writers are there with me, Glenn and Charlie. We just start throwing out ideas of episodes we'd like to do and things that we're not seeing anywhere else on television. We do that for 3-4 days and that gets us to the point where we have enough ideas and then we start trying to see what storyline will work with what storyline and then break it down from there. Generally, there's an overall thematic element that runs through the entire episode and then there are set pieces from that point forward.

For example, with [the season premiere], we knew we wanted to do something addressing my character getting fat and so we decided what would be funny about that is if Glenn and I went to the doctor and Glenn was going to prove to me how unhealthy I was and found out he's just as unhealthy as I am. We thought that would work really well with this particular storyline of Charlie trying to show Frank how he's worthy of getting a wonderful woman and pretending to go on this date. Also, someone had just wanted 'Pretty Woman' and said 'That is such a ridiculous movie and we're supposed to believe that Julia Roberts is a prostitute?' so what's the real version of that and like ingredients of a soup we just throw it all in together and stir it up.

JH: I have talked to Danny DeVito a few times now and he's a little all over the place in the best way. Does he sometimes need reigning in or does he - or the rest of the cast - stick to the script?

RM: If he needs to stick to the script, he'll stick to the script but that's sort of the way it works for all of us. We're very particular and specific about the scripts and we map them out and we'll read the scene and we'll set up 'Does this scene work?' So we'll do a few takes where we're doing it word for word in the script and then from there we'll just do whatever we want but we'll reign any one of us in at any given time.

JH: Was there an upside to gaining all that weight for the show?

RM: Yeah, without a doubt! First of all, I felt great throughout the whole process but I think that had to do with the fact that I was also working out. I wasn't doing any cardiovascular work but I was doing power lifting and I wound up just getting really strong and feeling really good and solid and then I just had to force down that food. That was a positive attribute but, also, just the complete lack of vanity was really liberating in a lot of ways, especially being in Los Angeles where there is this aesthetic, this completely ridiculous ideal where you have the most beautiful people from all over the planet move to this city and then most of us are not so beautiful. [Laughs.] I think ultimately there's this level of insecurity through the city, certainly our industry, and it was great to just literally say 'Fuck that! I look the way I look and I really don't care.' It was really liberating.

JH: Was there ever a point in the process where you were concerned you wouldn't be able to lose the weight.

RM: Nah. Ultimately, it wasn't easy to put on. I put on 50 pounds in five months so it was 10 pounds a month and there was a consistency with that. I just have the kind of metabolism that I can't put on weight very easily so it took a lot of discipline to put it on and then my body got used to it and now it's taking a lot of discipline to take it off. I was determined to gain it and now I'm determined to lose it.

JH: Where are you now? I believe at TCAs you had lost 25 pounds.

RM: I lost about another 10 so I'm about 33 pounds down from the 50 so I have about 17 pounds to go.

JH: Watching the first two episodes of the new season, there's a lot of blood. The premiere had the blood in the limo, which was hilarious, and then there's some blood in this week's episode. Is this a theme?

RM: [Laughs.] I don't think that was done on purpose. Ultimately, what we try to do is we just shoot the episodes and then we try to figure out what we want to air first in post because there is no real story arc. I don't know that that is going to be a theme throughout the season but it is in those first two episodes, that's for sure.

JH: There's a child beauty pageant episode coming up and it scares me to think what you guys might do with that!

RM: That was in answer to us wanting to find some of a more musical numbers to do. We had such great success with 'The Nightman Cometh' and had so much fun doing it but it's a lot of work because we're writing all the episodes and prepping the episodes but then you have to sit and write all that music and then do a great amount of rehearsal for the dance numbers. That being said, it's always such a good pay off and always works with us so we decided to do it with the pageant.

JH: What gets you guys into the pageant?

RM: You'll have to tune in and see but ultimately Frank thinks he's investing in an adult beauty pageant and it turns out it's actually children.

JH: The show is picked up for two more years so does that create any pressure or is it more of a relief?

RM: It basically says if there is an audience, there is a desire by the network and the studio to keep making it. There's definitely a desire from us to keep making it but it liberates us to know there are people who want more 'Sunny' and we're happy to give it to them.

JH: Are you ever concerned that you're running out of stories or is it not so difficult?

RM: When you're looking at a blank page and a blank screen it's always difficult to come up with a new story and then make that story funny. I don't think that will ever not be the case. However, it's still just as much fun as it was on day one so we'll keep doing it.

"It's Always Sunny in Philadelphia" airs Thursdays at 10:00/9:00c on FX.