Being asked to be Best Man at Jack’s wedding was an honour; when they’d first met the Doctor would have never imagined the incorrigible Captain would ever willingly settle down with any one person, committing himself to them for their lifetime, but then Ianto Jones was no ordinary man.
That being the case, the Doctor was determined to play his role to perfection. He wouldn’t let his old friend down. He’d have to take his companions with him, but he was sure Jack wouldn’t mind.
“I must get squinches for the ceremony! Can’t have a wedding without squinches!” he decided.