Meghan, the Duchess of Sussex, said Harry had “no idea” on some of the questions when she was preparing for the test.
The American-born actress spoke about studying for the Life in the UK test on the latest episode of her hugely successful Archetypes podcast.
She said she turned to Harry for help while practicing for the official government quiz, but the duke, who is fifth in line to the throne, was also stuck on the questions.
Chatting to actress and director Pamela Adlon, who recently became a British citizen, Meghan said: “That citizenship exam is so hard. I was studying for it and I remember going ‘Oh my goodness’.
“I would ask my husband ‘Did you know this? Did you know this?’ and he would be ‘I had no idea’.”
The Life in the UK test costs £50 ($57.65), lasts for 45 minutes and includes 24 multiple choice questions on British traditions and customs.
The score needed to pass is 75 per cent. The test can be rebooked an unlimited number of times, but applicants must pay each time.
Example questions include which king was executed in 1649 and who established the Church of England.
Adlon, best known for voicing Bobby Hill in the animated comedy show King Of The Hill, joked: “I think they made it harder for you. They were like ‘We’re gonna really throw up walls on this one’.”
Meghan laughed and said, “You think?”
When Meghan’s engagement to Harry was confirmed in 2017, Buckingham Palace announced that the former Suits star would become a British citizen.
But the Sussexes quit the working monarchy in 2020 and moved to the US, amid reports Meghan had abandoned the process of seeking citizenship.
Meghan also spoke about her family's “whirlwind” morning routine and how she makes breakfast for Harry, Archie and Lilibet every day, saying it is important to her and she loves doing it.
“Lili has just started walking. she's a year and a couple months old, and Archie's just over 3 years old, so … I'm in the thick of it. Toddling,” she said.
“So the morning rush — I'm sure it'll only get more chaotic as they get older. But for me, it's, you know, both monitors on for the kids to hear them, always up with Lili, get her downstairs, then a half-hour later Archie's up.
“Start doing his lunch box right before he's up, while I have her, getting her a little nibble. My husband's helping me get him downstairs. I make breakfast for all three of them. It's very important to me. I love doing it.
“For me it's just feels like the greatest way to start the morning. And then it's like feed all three of the dogs because we just got another dog and then get Archie out the door to school and, you know, but it does, it feels like a whirlwind.”
Meghan's mother Doria Ragland also featured in the podcast for the first time. She could be heard FaceTiming her daughter for a few seconds while the duchess was working on the episode.