The midfielder was wanted by the Seagulls in the summer of 2024 as they rebuilt ahead of Fabian Hurzeler’s first season in charge.
But he instead moved to Stamford Bridge and linked up with Enzo Maresca, who had been his boss at Leicester City.
Dewsbury-Hall failed to make an impact at Stamford Bridge and has since enjoyed a new lease of life with Everton.
Albion fans were unimpressed when he turned them down.
His decision was also bad news for Jakub Moder, who would have headed to the King Power as part of the deal.
Dewsbury-Hall told Sky Sports’ Monday Night Football: “Luckily as a footballer, when you have a good season, it can open many opportunities and many doors.
“I had a fair bit of interest at the end of that year but, as things panned out with the way Enzo Maresca ended being at Chelsea and I had worked with him, it felt like the right fit for me to go and play under him again at Chelsea.
“I did go to a club genuinely thinking I would play regularly. I knew I had the quality to do that.
“Unfortunately, I didn’t play as much as I would have liked but it was an experience I will never forget. I won two trophies.
“He knew me inside out as a player. He said exactly the way we want to play, ‘I love you’ and I don’t know exactly why I didn’t get the full opportunity.
“Of course I was up against top level players who were worth a lot of money and I didn’t really get the opportunity to get a run of five or six games.
“That was probably the most frustrating thing for me.
“I feel like every time I played I did well.”