Katie Boulter and Alex de Minaur kept their relationship a secret at the start

At the start of a new relationship, most young couples can't wait to launch their big news out into the world by way of a social media post, or for those in the public eye, a red-carpet appearance. But as tennis fans learned this week, that wasn't the case for Katie Boulter and Alex de Minaur at the beginnings of their romance four years ago.

In fact, as they revealed in a new video filmed at the Mutua Madrid Open, they were determined to do the opposite, and actively sought keep their blossoming romance a secret from the prying eyes of others on the ATP and WTA tours.

“Remember that time when we were having breakfast at separate tables?” Boulter asks, as the couple banters about love and life in Madrid's famous Retiro Park. De Minaur remembers, noting that they would "rock down to breakfast at different times."

“Different times, like 10 minutes later,” Boulter adds. "It's so true, so people wouldn't find out.”

“It works every time,” the Aussie responds with a laugh.

These days, the couple is more than happy to share their love with the world. Both have reached new career high rankings this year, even winning titles together on the same weekend in March, and have gushed to the press just how much they've learned from each other. Boulter, 27, said last year at Wimbledon that she admires her beau's temperment and professionalism on the court, while de Minaur says that Boulter has taught him to keep wins and losses in better perspective.

“He is the most down-to-earth person I've ever met," she said.

That authenticity was evident even as they navigated the early, unfamiliar days of their romance.

"I think what was very important, as well, in the early stages is that we talked about tennis being our number one priority, and we would make all of this work, just finding that balance. I thought it was going to be quite tough," he said.

"Now, sadly, we're spending more time together," the Aussie joked, to which Boulter responded: "I'm a great addition."

The sweet clip also sees the couple dish on their first date (for coffee, an offer that de Minaur previously that had Boulter initially rejected), compare themselves to pigeons frolicking around the park, and Boulter reflect on her own career journey. This time last year, she was ranked outside the Top 100, and hadn't yet contested a tour-level main draw on clay.

"Don't you think it's crazy how, like, this time last year, I was playing in Japan, I was ranked like 150. I was loving it," she laughs.

"I remember you telling me, 'I will not be playing a clay-court swing in my life, I refuse to play on clay.' And here you are, a whole year later, Top 30," he adds. "It fills me with a lot of joy, being able to tell you, 'I told you so.'"