Arnold only remembered the vital part of the ceremony seven minutes before he was scheduled to exchange vows with his fourth wife Ashley Groussman - when best man Dax Shepard took a moment to rehearse his speech.
Shepard recalls, "I had to get him to the altar on time, which is a very complicated thing for him. I was very smart and I got him to the house where he's getting married, like, two hours ahead of time. It was crucial because the sun was setting when they were going to say 'I do' and there would be pictures.
"Everything's going great and then about seven minutes before we're supposed to go out there I go, 'I'm gonna look at my speech,' and he goes, 'Oh buddy, you wrote your speech... You printed it out...? I'm gonna work on my vows,' and he pulls out all these five-by-eight sheets of paper and starts chicken scratching (writing).
"Apparently somebody had told him that day that he was getting married, because he had not prepared anything and now he's scribbling all these crazy notes... and I'm going, 'Tom, we're losing the light'.
"It turned out great, though."