No one told them the song was gonna blow up this way.

The Rembrandts were putting finishing touches on their third album, “L.P.,” when a sidestep into television drastically altered their course in 1994. Now, 26 years since “I’ll Be There for You” debuted on “Friends,” band member Phil Solem is reflecting on the ups and downs caused by the track, how a few beers led to its iconic claps and witnessing Brad Pitt enjoy a performance of the hit more than the cast.

Solem and bandmate Danny Wilde, who previously had a hit with 1990’s “Just the Way It Is, Baby,” will forever be associated with “Friends,” yet they initially asked to remain anonymous while working on the tune after viewing the pilot. “In those days, it was uncool for a band like ours to be involved in television,” Solem explains.

Musical director Michael Skloff had composed a piano melody, while executive producers Marta Kauffman and David Crane and late songwriter Allee Willis had started lyrics. Willis continued faxing through lyrics, which Solem tweaked. “They wanted an upbeat tempo and used R.E.M. – I think it was ‘It’s the End of the World’ – to vibe off, then we replaced it with our own sound.”

Solem was stunned when “Friends” blew up, taking the song skyrocketing with it. Soon, a Nashville station started playing the 42-second track looped to meet listener demand.

Seeing dollar signs, the Rembrandts were urged to extend the track into a full song for “L.P.” “We were making a dark, heavier rock album — the antithesis of ‘Friends’ — so we weren’t happy about that,” Solem says. “They’d already made 100,000 copies. I don’t remember if they recalled them or they ended up in a dustbin, but everything was reconfigured to accommodate this song.”

The pair completed the song, but Warner Bros. felt it wasn’t chirpy enough and brought Crane and Kauffman back to help write the final version, which was tagged onto “L.P.” “like a hidden track.” The song topped the charts globally and “L.P.” went platinum. “It went further than we ever imagined,” Solem says.

Nor did Solem imagine the song’s iconic claps, noting he and Wilde initially had lyrics in mind. “But we’d hammered back a couple of beers, were getting loopy and decided to finish the next day. The following afternoon, they played us what we’d done, but had added claps. I went, ‘Okay. That’s the hook!’”

So, where did the claps come from?

Executive producer Kevin Bright says it was all Skloff’s idea. “He and I are two of the clappers,” Bright confirms.

Over the years, fans have debated how many claps are in the song. And, they’re not the only ones wondering.

“When we were shooting the reunion, Matt LeBlanc asked me how many claps there were, and I didn’t know!” Crane shares. “Four? Five? I’ve heard that song a million times. For 27 years! I even wrote a bunch of the lyrics. How do I still not know how many claps there are?”

Enter Solem: “I don’t know how many times the question’s been asked. Anyone non-musical might think it’s five because there’s four of them, then a kick drum comes in and plays one.”

The cast and band later gathered around a coffee table in Jennifer Aniston’s New York hotel suite to prep for the music video. A script involving the actors knocking the band out with frozen fish was promptly canned.

“We all guffawed,” says Solem. “I think David Schwimmer said, ‘I’m not sure I like the idea of someone hitting somebody with a fish. We don’t need violence.’ We started throwing around ideas and none of the script made it in. Danny and I played the song and went along with whatever they made up.”

“Violence did factor, though,” the musician adds, “because Courteney [Cox] knocks the drummer out! And the girls take our sunglasses and end up with our guitars. It was nutty.”

Solem says Jennifer Aniston and Lisa Kudrow were the most fun, while Matthew Perry was the one they ended up back at the hotel bar with.

He describes the success that followed as “the golden albatross — it flew, just not in the way we expected”.

Suddenly on tour, the pair barely recognized their audience, filled with mothers and daughters hungry for “IBTFY.” Tiring of fans yelling “Friends!” throughout their set, they began opening with “IBTFY.” “Then we watched half the audience file out,” Solem says. “But over time it opened doors. We’ve got a whole pile of friends that came to us because of ‘Friends.’”

However, the fanfare took a toll on Solem, who began struggling with doing 4 a.m. interviews to serve heightened media interest, taking few days off and overworking his voice. “My vocal parts were way up in the stratosphere, so my voice would burn out and there was no day off to recover. It’s beyond embarrassing when you go to sing a high part and sound like a fraud.”

Having that coupled with lack of sleep, Solem “threw my hands up” and quit the band in 1997. He and Wilde later reunited, releasing 2001’s “Lost Together” and 2019’s “Via Satellite.”

But anyone who thinks “Friends” set Solem up for life is mistaken. While he receives royalties, he says his “IBTFY” fortune was largely swallowed by divorce. “If I didn’t have an ex-wife, I’d have a very cushy life.”

As for Thursday’s “Friends: The Reunion” special on HBO Max, the Rembrandts weren’t involved, but “IBTFY” still played its nostalgic part.

“When the song played and the cast came out for the first time in 17 years, it was very exciting,” Bright says. “It brought back a lot of memories.”

Solem remains close with James Michael Tyler, who played Gunther (“We hit it off in the early days. ‘Friends’ was the theme, but we became real friends, which was a sweet surprise”). But he hasn’t seen the core cast since the Rembrandts performed “IBTFY” at a 2016 event honoring director James Burrows.

“The ‘Friends’ table was right up front,” Solem says. “They sat there and pretended they were getting into it, probably thinking, ‘Again!?

“It’s funny because Jen had indicated she wasn’t into the song. But Brad was at the ‘Friends’ wrap party in 2004 where he looked like he was getting way into it! He was also, later, on ‘Between Two Ferns with Zach Galifianakis’ and they played it and his reaction was, ‘I like that song.’ Meanwhile, his ex-wife was apparently done with it. There’s that scene in ‘We’re the Millers’ where they play it and her reaction’s priceless. I hope she liked it at some point. She was such a nice person. Didn’t have a mean bone in her body.”

Despite the challenges it ignited, today Solem sees “IBTFY as “the gift that keeps on giving.” “I’m proud we did it, even though there was a period of wondering, ‘Did we make a mistake?’ More people today care about the rest of our music than if we hadn’t done it.”

He adds, “You try for years to become successful, then a little opportunity comes along and usurps the entire game plan. It’s been magical.”

Bright and Crane, meanwhile, are proud that the song made its mark before television theme songs became shorter and rarer.

“We were one of the last real theme songs,” says Crane. “I grew up on ‘Gilligan’s Island’ and ‘The Brady Bunch,’ but as shows have gotten shorter, so have opening credits. Today you barely get a three-second musical sting, so I feel lucky – like we got in just in time.”

“‘I’ll Be There for You’ proved that theme songs can be a powerful way to start a show,” adds Kauffman. “Ours took on a life of its own; people know all the words and clap in the right place. Who wouldn’t want that?”