The TOWIE star is one of 15 famous faces who will be taught to dive by mentor and Olympic diver Tom Daley.
A panel of expert judges will score the celebrities and viewers will vote for their favourite to determine who is crowned top diver.
"Joey Essex has a passion for wearing strange clothes so everyone is already waiting for the first show to find out what kind of trunks or Speedos he will be wearing on that diving board," a source told the Daily Star.
"He will no doubt be out to shock everyone."
Kate Price's ex-fiancé Leandro Penna and former Olympic skier Eddie 'The Eagle' Edwards are also said to be taking part.
Splash! will start in the New Year on ITV1 and will run for five weeks.