A lawyer for the family said the star had taken her own life.
She stood down from the dating show after she was charged with assaulting her partner in December and was due to stand trial next month.
As well as presenting ITV’s Love Island she had co-hosted The X Factor and won Strictly Come Dancing in 2014.
The family said in a statement: “We can confirm that our Caroline passed away today, the 15th of February.
“We would ask that the press respect the privacy of the family at this difficult time and we would ask they make no attempt to contact us and/or photograph us.”
Confirming Saturday night’s Love Island episode will not be broadcast, an ITV spokeswoman said: “Everybody at Love Island and ITV is shocked and saddened by this desperately sad news.
“Caroline was a much loved member of the Love Island team and our sincere thoughts and condolences are with her family and friends.”
From children’s TV to Chicago on stage
Many fans grew up with Flack since her breakthrough co-hosting Saturday morning show TMi with Sam and Mark on CBBC in 2007.
From there, she went on to front Gladiators on Sky One, ITV2’s I’m A Celebrity… Get Me Out Of Here! spin-off and The Xtra Factor, before moving to The X Factor itself with Olly Murs in 2015.
She cemented her popular appeal when she won Strictly Come Dancing in 2014 with partner Pasha Kovalev.
She is credited with making Love Island one of the biggest shows on British TV and was the one to pick up the award when it won the Bafta for best reality show in 2018.
The same year, Flack made her West End stage debut as Roxie Hart in Chicago and even appeared on the celebrity version of The Great British Bake Off.
At the time of her death, she had been replaced by Whitmore for the winter series of Love Island.
Flack was charged with assaulting her boyfriend with a lamp after police were called to her home in December.
She pleaded not guilty in court later the same month and was released on bail on the condition she did not contact Burton.
Her solicitor made an application to have these bail conditions lifted, arguing that they remained a couple and wanted to spend Christmas together.
In a statement, her management company criticised the Crown Prosecution Service for pressing ahead with what it called her “show trial”, even after her boyfriend said he did not support it.
Francis Ridley, of Money Talent Management, said: “In recent months Caroline had been under huge pressure because of an ongoing case and potential trial which has been well reported.
“The Crown Prosecution Service pursued this when they knew not only how very vulnerable Caroline was but also that the alleged victim did not support the prosecution and had disputed the CPS version of events.
“The CPS should look at themselves today and how they pursued a show trial that was not only without merit but not in the public interest. And ultimately resulted in significant distress to Caroline.”
In response, the CPS said its “deepest sympathies go to the family and friends of Caroline Flack”.
“Given the tragic circumstances, we will not comment on the specifics of this case at this stage,” a spokesperson added.