It may be too late for Morgan Stewart to say “sorry” toJustin Bieber.

Earlier this week, E!’sNightly Pophost slammed Bieber, 25, for hisCoachella performance on Sunday, in which the pop star joinedAriana Grandeon stage and was caught lip-syncing to his hit song “Sorry.”

“I did not realize it was going to be that bad,” Stewartsaid on the showbefore ripping into Bieber’s facial appearance. “He definitely looks like he put an Oxy pad on that forehead, but I don’t care. That is f—ed up!”

“@Morgan_Stewart just saw a video of you ripping me to shreds saying I was lip-syncing. They played the song and i just sang overtop of it,” Bieberexplained in his first tweet. “regardless why spend your time tearing people down. It’s people like you that are bullies at school that are making kids suicidal.”

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Morgan Stewart, Justin Bieber, and Ariana Grande

Justin Bieber/Twitter

Justin Bieber tweets about Morgan Stewart bashing his performance at Coachella

The singer, whose surprise performance marked thefirst time he was on stage in two years, then continued his argument and slammed Stewart for “belittling people” and hurting others.

“imagine if you spent even half the time you spend laughing at other peoples expense actually building people up and encouraging people how much positivity you could bring,” he wrote. “What hurts about this is the fact that you have a platform to make a difference”

“And rather than being positive you belittle people. Think about how awesome it felt for me to be on that stage after being away for so long the excitement and joy it gave me doing the thing i love the most, i sang to to backtrack like most cameos do this is a normal thing [sic],” he continued.

“And rather than try and make people feel accepted and loved you find things to pick apart like the world isn’t full of that already.. we can find something negative to say about anything or anyone”

In a final note, Bieber asked, “When are we gonna be the kind of people that find joy in adding value to one another and not tearing each other apart..”

Justin Bieber tweets about Morgan Stewart bashing his performance at Coachella

In a series of since-deleted tweets, the “thank u, next” singer, 25, defended Bieber for lip-syncing, explaining that their decision to perform together was not planned, which caused him to rely on the backtrack.

“we also decided to do this ten minutes before my set started. we had 0 soundcheck, 0 rehearsal,” Grande tweeted. “u were singing with the back tracking like most cameos do. people are bored. people don’t know how it feels to be under such scrutiny. the world was happy to have u on stage again.”

She added in a separate tweet: “i don’t like when people try to ruin beautiful moments for my friends that’s all. have a good day.”

Ariana Grande/Twitter

Ariana Grande tweets about her and Justin Bieber’s performance at Coachella

“people look so ugly when they talk about other people like this, it’s crazy. like no matter how pretty you are or how long u spent getting ready, u ugly to me now,” shewrote in the tweet, before asking, “HOW do people watch s— like this lmao.”

Representatives for both E! and Stewart did not immediately respond to PEOPLE’s request for comment.

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Justin Bieber and Ariana Grande.Kevin Mazur/Getty Images for AG

Bieber performs with Ariana Grande at Coachella

One week after Bieber wasfirst spotted at the annual music festival, he took to the stage with Grande during the end of weekend two.

“We thought it might be fun to do something for you guys,” Grande said before the pair, who are both onLil Dicky’s new single “Earth,”performed his 2015 hit.

“I haven’t been on stage in like two years. I came out here I had no idea I was going to be on stage tonight,” Bieber told the crowd. “So anyways this is my first time on stage in two years. I had to get my groove back, my swag back. By the way — album coming soon.”

Kevin Mazur/Getty

Justin Bieber (L) performs with Ariana Grande at Coachella

source: people.com