A short video was posted on the club's brand new account featuring Hoopy the Huddle Hound "announcing" the new signing.
However, supporters weren't best pleased at the club's left-field method of confirming the arrival of the Polish player on a four-and-a-half-year deal.
"Delete or I will go to the police" one fan tweeted the official account. Another wrote: "You are unbelievable. And I use that with negative connotation."
One supporter said: "Good plan this from the board, start announcing signings through TiKToK and eventually we won’t want to see more names coming in."
Paul Gray added: "If you think I'm wasting my time downloading the TiKToK app and creating an account just to watch a Celtic video, then you're absolutely f****** right."
A fan calling himself "Dave" moaned: "A tweet would have done" while another supporter instructed the club to "unannounce it and do it normally please".
Tam the Celt said: "Nah, nope f**** that. I’m all for the esports stuff and disco lights, imaginary hotels, signing Jack Hendry and Scott Allan for a laugh but TiKToK crosses the line, we should liquidate ourself for that."
Supporter Catholic Goth typed (in block capitals): "JUST ACT NORMAL FOR ONCE."
Quinny88 tweeted: "We have become a banter club, delete this immediately."
Rachael added: "Please don’t do this again Celtic, I’m too old for this nonsense!"
Jake McCann revealed: "I now support Rangers" while Ryan Duke replied: "Get in the sea. Announcing a new player on TiKToK."
Dean Robertson had some instructions for Celtic: "Look, we’re in our late twenties here, we’re not moving from Twitter to TiKToK lads, announce Polish Paddy in the traditional, Twitter fashion or we riot."
Mike Boyle added a popular meme with the words: "The best time to delete this tweet was immediately after sending it, the second best time is now."
One supporter wrote: "Well, ok, we'll get our weans to tell us what was on it. Thanks."
Andrew McGilveray tweeted Partick Thistle to ask how much a half-season ticket at Firhill would cost him while Damon Weir branded the video "tragic".
At the time of writing, TiKToK was trending in Scotland on Twitter.