The royal cousins are very close and share regular updates about work and family life in their shared WhatsApp group.
Princes William and Harry, Princess Beatrice, Princess Eugenie and Zara Tindall can always be seen chatting at official royal events and enjoying private jokes together.
But there was one rather cheeky comment Zara was caught making to Harry that might have caused a bit of awkwardness behind the scenes, reports the Daily Mail.
While we're sure it was just a bit of fun, the Queen's granddaughter's quiet words about Eugenie's royal wedding could have got her into trouble with her more-senior cousin.
Harry and Zara and their partners Meghan Markle and Mike Tindall had some of the best seats in the house when Eugenie married Jack Brooksbank in October 2018 at St George's Chapel in Windsor.
However as Zara took her seat she made a passing comment to Harry which could have caused some upset.
She was seen leaning back to say a few words to Harry about his own wedding to Meghan, which had taken place a few months before.
According to a lip reader, she told the prince: "It's very quiet compared to the screaming at your wedding."
In response, he asked: "Mine?"
Eugenie and Jack picked the same wedding venue as the Sussexes for their special day, but they were very different occasions.
Despite Harry being more senior than his younger cousin, Eugenie actually had more guests, which Prince Andrew said was because his daughter has "so many friends".
Both guestlists were filled with celebrity guests, with George and Amal Clooney, Oprah Winfrey and the Beckhams joining the royals for the Sussexes' big day.
Meanwhile, Ellie Goulding, Cara DeLevigne, Demi Moore, and Naomi Campbell were at Eugenie's.
Eugenie was reportedly upset at her wedding when Meghan used the occasion to tell members of the family she was pregnant.
The couple told the world they were expecting their first child on the eve of their royal tour of Australia and New Zealand, but shared the happy news with close family at the evening reception.
To receive one WhatsApp message a day with Edinburgh Live's headlines, as well as breaking news alerts, text NEWS to 07899067815. Then add the number to your contacts as 'Edinburgh Live'.
In their book Royals at War, investigative journalists Dylan Howard and Andy Tillett claim Meghan made the decision to tell people - and it didn't go down well with Harry.
They claim that it left the Duke of Sussex "embarrassed", and Princess Eugenie and her mum Sarah Ferguson "furious".
They write: "Meghan put her foot in it when she decided that it would be the ideal moment to announce that she and Harry were expecting their first child.
"This was a huge social gaffe, even if you were not a Royal – stealing the limelight from Eugenie, who was furious, as was her mother, Sarah."
