Before the success of her cult-hit musical-comedy series, “Crazy Ex-Girlfriend,” star and co-creator Rachel Bloom faced her fair share of rejection. When she pitched the series, Netflix, Amazon and FX (to name a few) all said no. Showtime said yes, love it . . . until suddenly, they were just, nahhh, never mind.

But last year The CW took a chance on Bloom, 29, an up-and-comer with no TV experience but some raunchy YouTube videos that had gone viral — and it paid off. She nabbed a Golden Globe (for best actress in a musical or comedy) and two Emmy nominations (for songwriting).

Now in its second season, the show follows the travails of Rebecca (Bloom), a delightfully neurotic (or seriously demented) attorney who ditched Manhattan for West Covina, the Los Angeles suburb where her ex, Josh (Vincent Rodriguez III), just happens to live. She insists she’s not obsessing, but her new SoCal pals Greg and Paula (Broadway vets Santino Fontana and Donna Lynne Champlin) know better. This being a musical, they all sing, in killer parodies of everything from boy bands and hip-hop videos to Fred-and-Ginger dance numbers.

You’ve got some serious New York theater actors in the cast. Were you avoiding L.A.?

We had an L.A. casting director, but for the pilot we hired one in New York because this is a musical, and — to be frank — it demands diversity, especially for the role of Josh Chan (who’s of Filipino ancestry). New York theater has more roles for people of color. I think the whole cast of “Here Lies Love” (the Off-Broadway musical about former Philippine First Lady Imelda Marcos) auditioned. Then there’s Donna Lynne and Santino — their acting auditions were so good, we’d have hired them even if they couldn’t sing.

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Do you approach the show differently now that you’re in season 2?

The whole premise of last season was “denial.”

As in, “Obsessing over my ex? No way!”

Yeah. This season, it’s about the unbridled pursuit of what you want.

Now you’ve got some TV street cred, but I gather this show was a tough sell originally.

I pitched two musical shows before this, and no one cared. Having a respected writing partner on it — co-creator Aline Brosh McKenna [who wrote “The Devil Wears Prada”] — gave us clout.

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How do you have time to act and write music for the show?

I write more of the music when I can sit down at a piano and really think it through. Into the season, my contribution is more finding a song’s rhythm. We’re working on one now for episode 12. I walked around the studio, jotted down ideas, came up with a rough chorus, which is always important — that’s your thesis statement. Jack Dolgen, a music writer on the show, crafted a song from my notes. On the plane yesterday, I wrote a bridge, and Jack just emailed 10 minutes ago saying, “Hey, I think the bridge should be more like this.” I texted him lyrics off the top of my head. So it’s all very . . . on-the-fly.

I hear Patti LuPone shot a guest appearance for later this season.

She’s amazing. So chill. There was no ego. She just walked on and had fun with us.

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Whom does she play?

Someone from Rebecca’s past.

Mysterious.

Mmm hmmm.

And she sings?

Yes.

C’mon, gimme a hint.

She may or may not have a scene with Tovah Feldshuh [who plays Rebecca’s nudgy Jewish mother], and it may or may not be the greatest thing to have ever happened.

Intriguing. Why do you think people seem to have such a visceral reaction to musicals? So many either love them, or hate them.

Many reasons. First, songs for musicals used to be pop songs — from the 1920s through the ’60s. Frank Sinatra sang Cole Porter. Rock and roll changed that. Suddenly, show tunes became all “showtunesy.” Also, musicals are all about the suspension of disbelief. People who don’t like musicals tend to be boring and uncreative, because they can’t suspend their disbelief.

You’re not coy about this.

Look, the other problem is that a lot of new musicals are crap. And some revivals, of shows that were good in their day, are just dated. But when a musical is good, it influences you. Take “Hamilton” — people who’ve never liked musicals before love that show. People tell me all the time, “I normally hate musicals but I really like your show.” It’s like, OK, well, that means you don’t hate musicals. The golden age of musical theater was the ’40s through ’60s, and if that’s not your cup of tea, fine. But there’s a lot more choice out there. When people’s knee-jerk reaction is, “Oh, I just don’t like musicals,” I think, “Ehhh, ehhh, ehhh.”