In his statement, Prince William said of the new inquiry: "It should help establish the truth behind the actions that led to the Panorama interview and subsequent decisions taken by those in the BBC at the time".
Click inside to find out how the Harry source is responding...
In the past few days some newspapers have carried criticism of Prince Harry for not "standing by" his brother, the Duke of Cambridge.
Although fans love the season, the same can not be said for Prince William and the royal family, who have a long history of disapproving of the series and its portrayal of their family.
"Harry is getting regular updates and is aware of everything that is happening", the source told the BBC.
Lord Dyson will be looking into allegations made by the Princess of Wales' brother, Charles Spencer, earlier this month that accused BBC journalist Martin Bashir of using forged bank statements and false claims to convince her to participate in the interview.
The broadcaster has appointed a retired judge, Lord Dyson, former master of the rolls, to lead an investigation into the Diana interview.
What will the investigation look at?
But on Friday, Earl Spencer questioned the scope of the probe.
Britain's Prince Harry has joined his brother William in welcoming a new investigation into how the BBC secured a famous and controversial 1995 interview with their mother Princess Diana, with a source describing it as a "drive for truth".
"Lord Dyson must be free to examine every aspect of this matter, from 1995 to today, as he sees fit". Will said, "The independent investigation is a step in the right direction".
On Thursday, TV watchdog Ofcom said it will not launch its own investigation into the BBC Panorama controversy, but will follow the independent inquiry "closely".
The BBC has insisted that investigation has a sufficiently broad scope.
Nearly 23 million people tuned in to watch the Panorama programme 25 years ago.
The interview, in which Diana admitted there were "three people" in her marriage, was watched by 23 million people and sent shockwaves through the Royal Family.
The season just dropped, but critics are already calling it the show's best broadcast yet, praising the performances of Emma Corrin and Gillian Anderson who stole the scene as Princess Diana and Margaret Thatcher.
A month later, the Queen urged the separated couple to divorce, which they did in 1996, a year before she died in a vehicle crash in Paris.