McClenaghan, from Co Down, is recognised as one of the best pommel horse specialists of his generation.
The 25-year-old made history when he became the first-ever Irish gymnast to win an Olympic gold medal in the sport this summer.
Last year he was named as RTÉ’s Sportsperson of the Year.
“I am approaching my training for the 2025 competition year differently. I took some time to travel, and as I begin my first training block for the LA Games, I will also have some fun figuring out how to dance,” he said.
Each new contestant spoke to Late Late Show host Patrick Kielty last night about competing for the coveted glitterball trophy on RTÉ next month.
They were joined by dancer Karen Byrne, who is the newest judge to join the adjudicating panel. Ms Byrne is a two-time winner of the show.
Also announced as a contestant was Cork broadcaster Elaine Crowley.
She is one of the country’s most popular television presenters, co-hosting Ireland AM, as part of a two-decade career in daytime TV.
Crowley (47) has spoken frankly about being diagnosed with dysphoria – a feeling of profound unease or dissatisfaction – and has also spoken about overcoming dark periods in her life.
She spoke of how her eldest sister urged her to push herself out of her comfort zone, saying, “You can interview the politicians. You can do all the stuff on Ireland AM, but challenge yourself for once.”
The third household name is celebrity chef, presenter and author Kevin Dundon (58).
He has presented shows such as Guerrilla Gourmet and Heat, as well as having cooked for Irish and US presidents and the late Queen Elizabeth.
“As a chef, I’m co-ordinated, but not with my feet. My first dance is an American smooth, so I’m going to treat it like a risotto – nice and slow with a little bit of excitement at the end,” he said.
Also announced was Kayleigh Trappe, a social media star from Co Monaghan who previously worked as a primary school teacher. She has amassed 400,000 followers and millions of likes on TikTok and Instagram for her lip-sync comedy sketch videos.
Speaking of the announcement, she said: “I’m so excited. It feels so surreal, especially because I’m so used to just being behind the camera in the comfort of my own home, and now I’m going full glitz and glam. It’s a big change, but I can’t wait to get the glitterball rolling.”
The fifth contestant is Dubliner Yasmin Seky, best known for her breakout role in the RTÉ drama series Kin, in which she played the role of Nikita.
“I’m a little nervous… with acting on screen, if you mess up you can go again. But with this, you get one shot and you just have to make it happen,” she said.
The five join other hopefuls announced earlier this week: singer-songwriter Mickey Joe Harte, Irish taekwondo Olympian Jack Woolley, comedian Gearóid Farrelly, Mrs Brown’s Boys actor Danny O’Carroll and former Miss Universe Ireland, Aishah Akorede.
The final celebrity will be revealed tomorrow morning to complete the Dancing with the Stars class of 2025.