The Diary can reveal how Chris -- the chief executive of 98fm -- put some military-style planning into popping the question in order to keep it a huge surprise from his other half.
"I'm absolutely made up. I actually forgot to say 'yes' to Chris as I couldn't speak for a full minute after he proposed. I was in total shock, it was the last thing I expected but then there was lots of hugging and of course I agreed," Sean (30) explained.
Sean, who presents FM104's The Juice, has been dating Chris (30) for more than seven years and the pair are now due to follow in the footsteps of Alan Hughes and Karl Broderick with another high profile same-sex union.
However, his fiance had to engage in some seriously sneaky tactics in order to keep his plans secret -- even resorting to inventing press trips abroad.
"I'd been in Brighton the previous day and had flown back home to Dublin, then back to London the next morning for what I thought would be a press screening with Universal Pictures, so I was absolutely shattered," said Sean. "Chris had got up even earlier than I had, saying he had to go to Limerick for work when actually he had flown to London at 6.30am and checked into a hotel so he would be there before me.
"I was picked up at the airport by this Mercedes and brought to this amazing hotel called the Corinthia and I remember thinking, 'God, Universal are really pulling out all the stops.' When I got up to my room, Chris was there waiting there for me.
"He had been tracking the car on his iPad so he would know when I got there. I was so confused I was like, 'Chris, what are you doing here? I have to work'. Then he proposed and everything fell into place. Universal Pictures had been in on the plan from the start so it was a lovely surprise."
Chris then whisked off Sean for a weekend of pampering, bringing him firstly to Claridge's for afternoon tea and then on to Gordon Ramsay's acclaimed restaurant for an evening meal.
Sean added how the good news still hadn't sunk in -- but they are looking at tying the knot in 2013. And he said how great it was that couples like Alan Hughes and Karl Broderick had helped take away any stigma surrounding same sex unions in the wake of the Civil Partnership Act being introduced.
"I had a quick look at some websites and there's no shortage of places and venues where you can have civil partnerships so it's absolutely brilliant that it's not seen as something out of the ordinary anymore," he added.