23-year-old Jack is the eldest son of the Boyzone singer and his ex-wife Yvonne Connolly.
Jack Keating, who works in social media marketing, joined the show alongside five other boys as part of the programme's famous Casa Amor twist.
The twist sees couples in the Love Island villa split up as six new boys move in with the girls and six new girls move in with the boys as part of the ultimate relationship test.
Taking to social media, viewers had a mixed reaction to the Dubliner appearing on the show, with many saying he looks way too young to be on the programme.
“Right who let their 15-year-old, called Jack, get tattoos and come on Love Island?” one person asked.
“Jack is fresh out of primary school wtf,” added another.
A third said: “Nice of Jack's mam to drop him off at the villa. He's gonna be f**ked when they're expected to stay up past 9pm.”
Meanwhile, fans of fellow Irishman Dami Hope, who entered the villa on day one, say he is the only Irish representation the show needs.
“Excuse me Jack, Dami is the only Irish charm we need thank you,” said one person.
“Sorry Jack but Dami is the only Irish person in my eyes,” added another.
“Jack p**sing away Dami's good work for Ireland,” a third joked.
Speaking ahead of appearing on the show, Jack said his famous dad would tune into the show to root for him.
“My dad is a singer, Ronan Keating. He will be watching when I'm on it for sure.”
“He's buzzing for me, me and my dad are very close, we're best mates,” he added.
Jack said he’s been single for almost five years and is looking for a spark.
“Hopefully I'll get a connection with somebody and see what happens.”
The singer’s son said he is not afraid to step on some toes.
“I'm very competitive, for sure. I play rugby back home in Dublin and in London so I've definitely got that competitive edge,” he added.
Jack’s younger sister Missy Keating recently put rumours to bed that she was set to enter the show.
“I’ve heard the odd rumour,” she told sundayworld.com
“You’ll have to just tune in and see!” before clarifying: “No, you won’t [see me]. I’m only teasing!”