On Wednesday, artists including Lana Del Rey and Dua Lipa had their biographies replaced by the attacker.
The hacker called himself Daniel, and replaced the celebrities' photos with one of himself.
The action will be an embarrassment to the platform's security efforts. It is the most popular app of its kind.
The attacker also asked people to add him on Snapchat, and added the words "Trump 2020".
"Best of all shout out to my queen Taylor Swift," he added.
