The Duke and Duchess of Cambridge are a strong support for each other, and they always seem their happiest and most relaxed when they're together.
While they're not as affectionate as Prince Harry and Meghan Markle, the couple are always giggling and exchanging cute glances - to the delight of their fans.
And according to royal expert Katie Nicholl, Wills is a bit of a romantic and would have made sure his wife "felt special" on Valentine's Day.
She told OK! magazine: "I don't know if he'd admit to it but deep down William's a bit of a romantic. He'll make sure Kate's made to feel special on Valentine's Day."
While we don't know exactly what they got up to, Katie has a few ideas about how the Cambridges might have spent the special day.
She said: "I think they'll probably use the date as an excuse to spend some time together."
"They do have a favourite Italian restaurant in Kensington just a stone's throw from the palace, and William has been known to treat Kate to a romantic meal there.
"But it's very hard for them to go anywhere undercover.
"There's a sweet side to William so I'm sure there will be a card and a thoughtful present for Kate, and perhaps a quiet dinner at home."
Kate and Wills met at university and were good friends before their romance blossomed.
The couple famously split for a period while they were at university , and although they've spoken about it there is still a lot of speculation about what made them decide to temporarily call time on their romance.
According to one royal expert, the split may have happened because the then Kate realised exactly what she was taking on by dating a member of the Royal Family.
Judy Wade, former royal correspondent at Hello! magazine, said: "She might have realised the awful burden she would have taken on.
"It’s a life sentence marrying a royal."
The Duke and Duchess spoke about their brief split in their engagement interview, and Kate admits it made her stronger.
William said: "We did split up for a bit.
"We were both very young, it was at university and we were both finding ourselves and being different characters and stuff.
"It was very much trying to find our own way and we were growing up.
"It was just a bit of space. It worked out for the better."
But they managed to work things out and Wills popped the question in Kenya, with the couple tying the know at their Royal Wedding in 2011.
