Rex Orange County headlined two packed shows at The Fillmore in Fishtown this week. The singer-songwriter is nearing the end of his tour in support of his latest album “Pony,” which was released last fall.

Rex Orange County, born Alex O’Connor, is an alternative artist that grew out of the bedroom music scene. His first album “Bcos U Will Never B Free” caught the attention of Tyler the Creator who subsequently featured him on his grammy-nominated album “Flowerboy.” Rex Orange County’s sophomore album, “Apricot Princess,” was a huge step forward from his debut, and earned him his own cult following. The music was much more fleshed out, with stronger songwriting and elaborate and lush instrumental production.

On his latest album, the 21-year-old indie bedroom matured into a major-label backed alternative artist. So it is fitting that the tour sees him headlining his biggest venues to date. And, in most cases, he is selling out those rooms.

On Monday night, his young fans lined up waiting for the doors to open at The Fillmore. The line stretched the length of the parking lot and around the corner. It was obvious people were eager for the show and didn’t want to miss a minute of the set since there was no opener.

Rex opened the show with the upbeat lead single from “Pony,” “10/10.” It was an appropriate choice, being on the more energetic side of his catalog. He took the stage to a crowd screaming along with every word. The crowd sang along to almost every song throughout the night getting especially loud during the more riotous tracks like “Television / So Far so Good,” “Never Enough,” “Best Friend” and “Sunflower.”

The stage started as a cloudy sky, something almost out of a comic book. The ground was adorned with turf and white flowers. Though he makes his music by himself, he tours with five band members – a drummer, bassist, guitarist, trumpet player and one man who plays the saxophone, keyboard, guitar or flute depending on what the track calls for. It was very impressive to see some of the more intricate songs, like “Television / So Far so Good,” brought to life with the band.

In the middle of the set, a curtain came down hiding the band. Rex Orange County played some of his slower, stripped back songs by himself and a cover of Alicia Keys’ “No One.” It was here that Rex took the time to talk with the audience a bit more. He thanked them for their support and asked them to keep singing along.

As he began “Never Had The Balls,” the curtain came down to reveal a full set change. The clouds had been replaced with a gigantic silver inflated pony and disco balls. It was a great way to signify the mood change within the setlist, with the energy picking back up for the next few songs.

The show ended with more down-tempo tracks “It’s Not The Same Anymore” and “Always.” It was a bit weird for the music to slow back down to bring us home, but the crowd was still singing their hearts out.

Rex Orange County puts on an extremely musical and fun show. If you are a fan, you should definitely look to catch him live if you can get tickets before it sells out.