Couple left mortified after best man delivers incredible punchline during speech

One of the best best man's speeches ever.

One man took a real gamble at his best friend's wedding as he delivered the "best punchline ever" during his best man's speech. There aren't many greater responsibilities in a male friendship than being bestowed with the honour of best man. But this of course comes with the huge pressure of having to put together a speech worthy of your friendship, that will hopefully have the room in stitches. Some men can crumble under the pressure - think Smithy in Gavin and Stacey - others thrive - like Derek. In a viral video, Derek is delivering a speech at his brother Gary's wedding. Gary had tied the knot with his bride Kirsty at Doubletree Dunblane Hydro in Perthshire, Scotland. It's safe to say that Gary wasn't ready for what he was about to hear. He says: "One Christmas morning, I got up in my mum and dad's house, buzzing I may add. Walked down the stairs to open my presents only to be greeted with a slap from my mum. 'What did I tell you about bringing folk back here?'

"I say: 'What are you talking about mum, I've been in my bed the full night'.

"Obviously she's not thinking about golden child next door."

Derek continues: "So we're in the living room opening a couple of presents, me, my mum and my dad, and we hear rustling from the wee room in the auld house, as we called it. "At this point, I go up the stairs, open Gary's room, and there you have it, Kirsty Currie, lying with her legs at ten to two.