Prince Harry has not yet asked his brother to be his best man, the Duke of Cambridge disclosed tonight as he joked he is "still working" on the diary clash that sees the Royal wedding on the same day as the FA Cup final.
The Duke, who is widely expected to perform best man duties at his younger brother's wedding to Meghan Markle in May, said he had not been officially invited to step up to the role, as he joined a discussion of what makes a "best man".
Asked by footballer Rio Ferdinand about an awkward clash of dates on May 19 which meant the Duke is likely to miss the football, he replied he was "trying to see what I can do" about the situation.
The Duke was invited to join a group discussion at the Campaign Against Living Miserably (CALM), a charity aimed at preventing male suicide through open discussion which has recently launched a "Best Man Project" celebrating men's friendship.
Roman Kemp, compering, highlighted the Duke's own role as best man in the coming months.
Laughing, he replied: "He hasn't asked me yet, just to clear that up. It could be a sensitive subject."
The Duke went on to speak about his relationship with his brother, emphasising the importance of men speaking openly to one another about their emotions.
"Our relationship is closer than it's been because of the situation we've been through," he said.
"Losing our mother at a young age, it's helped us travel through that difficult patch together. You're like-minded. You go through similar things, it's a bond and it's something you know you've tackled together and come out better for it.
"That's the thing about being a best mate, inevitable one of you is sometimes on an up while the other is on a down.
"You're always there for each other and repaying that favour."
Of his own approach to discussing his feelings, following his mother's death, the Duke continued: "Personally I didn't want to be a burden. So I knew that if I trapped this inside and it got worse, and inevitably I would get worse in the future and I'd be a burden to my friends and family.
"I didn't want that for my life. I didn't want the traumatic moment that happened to me to then affect me for the rest of my life and I knew my mother wouldn't want that for me either.
"So I actively went around dealing with it. Talking about it."
Arguing men can be the worst for opening up, he added: "We've got to break that down where it's ok to talk. Sons, fathers, it's ok to have that chat.
"Someone's got to be the brave one and take the first step. Say I'm putting it out there: that upset me, or that pissed me off. You've got to take that initial step to bring that conversation to a head."
CALM is one of the key charity partners of Heads Together, the campaign led by The Duke and Duchess of Cambridge and Prince Harry.
The charity is particularly focused on services for men in crisis or distress, in an age where suicide is the single biggest killer of men under the age of 45 in the UK.
The Duke has previously spoken of being called to a suicide on his first shift as an air ambulance pilot, and how it has informed his charity work since.
Their long-term campaigning is directed at bringin about a culture change to "redefine and open up masculinity, so that over time fewer men will need support at crisis point".
CALM recently launched the 'Best Man Project' to promote the idea that men do not have to wait until a wedding to prove they are a great friend, encouraging them to be proactive in looking out for their mental health.
CALM said: "Being a best man is an honour.
"Being a best man is often a shining example of what it means to be a great mate.
"From the moment they’re asked, many men display exemplary behaviour – from planning the stag do, to carrying the rings and engineering the laughs while reminiscing to a room full of people.
"At CALM, we’re of the belief that you don’t need a wedding to be a best man. In fact you can be a best man all though your life."