But it's an honour that comes with a caveat. As best man, you'll get a haircut. You'll be dressed up in a fancy suit. You'll be photographed with some pretty ladies. And you'll be required to perform 10 to 15 minutes of edgy, borderline offensive stand-up comedy in front of a crowd comprised mostly of strangers.
And once you're in, there's no backing out - as evidenced by Welsh soccer international Chris Gunter last week. The player was due to be the best man at his brother Marc's wedding in Cancun, Mexico on Thursday - the day after his side had a historic face-off against Portugal in the Euro 2016 semi-finals in France. With Gunter's parents also opting to attend the match rather than the wedding, which had been booked months ahead of Wales' unexpected progress in the competition, the defender was facing into delivering his speech via Skype.
So, how exactly does one go about writing a best man's speech? Ostensibly, a best man's speech is a bit like a Comedy Central roast, wherein your primary duty is to ritually humiliate the groom in front of his assembled guests, with as many embarrassing and off-colour anecdotes as possible. That's what your friends will want. Hell, that's even what the groom will be expecting.
Unfortunately, your audience on the day won't just be your knucklehead mates. The audience will also include the groom's parents (except in the case of the Gunters!), his family, his partner, his partner's family, plus a whole swathe of people who don't know either of you from Adam.
For the groom's sake, and your own, it's probably best not to alienate these other people entirely. When it comes to composing the speech, therefore, imagine you're playing a piano that only has two keys: funny and heartfelt. You can hit either of those key as many times as you like. But you cannot keep hitting one to the exclusion of the other.
The jokes can be vicious if you want, as long as it's clear that they're coming from a place of love. The bottom line has to be that the groom is a good guy, who will make a good husband for his new spouse. (And if, in fact, the bit about him being a drunken buffoon is closer to the truth of the matter... What harm? You can deliver the director's cut of your speech at 3am in the resident's bar.)
As someone who has spoken at three weddings myself, and written best man's speeches for many, many others, here are my DOs and DON'Ts for writing a great best man's speech…
DO: Cast a wide net
Talk to people at the stag party. Gather stories and anecdotes that recall the groom as a brother, a son, a colleague and a friend. Arrange the best of these, as well as your own memories, roughly in chronological order. You're not going to tell the guy's life story, but you should try to convey some impression of him as a boy, a young man and finally as an adult.
Don't: Dwell too long
Try not to concentrate too heavily on any one aspect of his life to the exclusion of all else. One tale of him passed out with his head in a toilet bowl is fine. Two is perhaps too many.
DO: Trim the fat
Type up each story you plan to use. Run a word count on what you've written. Now type up the same story a second time, keeping all of the important details, but using half as many words. Find the shortest possible route from set-up to punchline. Then move on.
DON'T: Worry about nerves
Nerves are natural. Nerves are your friend. Nerves will win you the audience's sympathy and prevent you from coming across like an overconfident idiot. A wedding is about the friendliest audience you could possibly ask for. You're among friends. They'll all want you to succeed. There's really only a handful of ways you could squander that goodwill - and we've listed them all for you here.
DO: Keep it (reasonably) clean
Overt references to sex, violence and/or illegal drug use are definitely best avoided in a best man's speech. Remember there will be kids, grandparents and aged aunts in attendance.
But by the same token, be mindful that just about any anecdote can be effectively sanitised through the use of polite euphemisms and judicious editing.
Say, the first time he got drunk, the groom had a "minor difference of opinion" with the local constabulary.
Backpacking in Thailand, perhaps he got "more than he bargained for" after befriending a "friendly, exotic local." In his college days, he had a "brief dalliance" with the local cumann of Young Fine Gael. (Actually, spare them that last one. Some skeletons are best left in the closet.)
DON'T: Get drunk
If you choose to ignore every other point I make here, heed me on this one. Most wedding ceremonies take place around lunchtime. Your speech may not take place until 8, 9 or 10 o'clock at night. So while your friends may start knocking back pints the moment they hit the reception, it is highly advisable you do not follow suit. Have a glass of wine with your dinner, if you must. But leave it at that. You have been warned.
DO: Lavish compliments
Compliment the groom's new spouse. Compliment his mother. Compliment the groom's mother. Toast the bridesmaids. Toast the priest. Toast the waiting staff. Toast anything that moves, basically. The brownie points you rack up here might just save your skin later on when it gets to, you know, the ladyboy stuff.
DON'T: Dabble in in-jokes
These are the "hilarious" inside references that will have a handful of the best man's close friends in stitches, while leaving the rest of the room bewildered. One in-joke, at a stretch, might just about be acceptable. But any more than that would be extremely ill-advised. Short of being drunk, this is the most sure fire way to alienate an audience.
DO: Be original
There's a vast stock of wedding jokes on the internet, but the audience will have heard them all before. And even if they haven't, those jokes are so generic it'll be obvious to everyone this one came out of a cracker.
I was at a wedding once where the best man stood up and said "Ladies and gentlemen, if I could just say a few words… I'd be a better public speaker."
Even the bride and groom just looked at the floor. He lost the room and never won it back.
DON'T: Run your jokes by your mates in advance
Counter-intuitive, I'll admit. Professional comedians regularly workshop their material in small venues before going out on tour. The problem for you is that, if your mates know the punchlines in advance, they're not going to laugh. And they're the very people you're relying on to do the heavy lifting, laughter-wise. Aged Aunt Mildred ain't going to be the one busting a gut at your Amsterdam ping pong ball story, believe you me. At a push, if you must run your jokes by anybody, run them by someone who won't be at the wedding.
DO: Be discreet
There should be no mention of either spouse's previous relationships. None. If you hadn't figured this one out already, you may actually be too stupid to do this job.
DON'T: Fail to prepare
Once you've assembled a draft, practice reading it. If there are any words or phrases in it that don't sound like you talking, change them. If there are any anecdotes that don't work, cut and replace them. By the time you deliver this speech, you should be so familiar with it you could almost recite it from memory.
If your speech is bad, all the charm and confidence in the world won't save you. But if you put in the work, it doesn't matter how nervous you get, you're on to a winner.
Thinking outside the box
Looking to do something a little different? Here are some alternative best man speech ideas.
This is a humorously narrated photo slideshow presentation of the groom's journey from boy to man. The approach works best if the two of you are brothers, and you therefore have access to pictures of him engaged in a wide variety of activities throughout his life. (As opposed to 25 photos of you and the groom drinking pints in the college bar in 2003-07.)
But be warned: getting a projector, making sure it works and ensuring all of the guests can see the screen will take a fair bit of advance preparation. And as far as staff at the reception venue are concerned, helping the best man will be at the very bottom of their priorities on the day. So don't expect co-operation to be a given.
Video skits are another idea that have become popular in recent years. Obviously, the same warning about logistics as above applies here. Beyond that, this approach, frankly, is fraught with risk. If there's a funny, original idea that you're confident you and your mates have the technical know-how to pull off, by all means go for it. Otherwise, it smacks a little of hard work. You're putting a whole lot of pressure on this video to get a big laugh and, if it doesn't, you may just end up with egg on your face.
Messages from absent friends
This is where you contact any friends of the bride and groom who are living abroad, or can't make the wedding for some reason. You ask them to email you a special message for the happy couple, which you will read at the reception. None of this "love and best wishes" rubbish. Stipulate that you want a proper personalised message: whether a poem or a special memory or dedication
Honestly, this one is a doozy. The bride will well up when the message is read. The uncles and aunts will go "aww!" And you'll have just conned some chump into writing a whole chunk of your speech. Bingo! Everyone's a winner.