The couple's son, Alex, was getting married. And he hadn't given them a lot of notice.
"He got married out of the blue," Di, 73, tells TV WEEK. "He's on a student visa – there were complications marrying an American. It was like, 'OK, it's in two weeks.' So we went, 'All right,' and we were there."
Di says it was a nice surprise when Alex, who's just turned 41, broke the exciting news.
"I thought we were going to have him forever," she laughs.
Now Di is hoping her son and his "adorable" wife, Andrea, will have children.
"I haven't said anything, but we'll keep our fingers crossed!" she says.
But the reality stars already have one grandchild, Harvey, who's sure to keep them busy for now. He's the son of their 38-year-old daughter, Victoria.
"He's two-and-a-half," Di enthuses. "I have him one day a week. He's a total live wire. He is action-packed."
For Mick and Di, their son's nuptials couldn't have come at a better time. After all, they celebrated their 50th wedding anniversary just last year.
So what is the secret to their long, happy marriage?
"Patience – on my side," Mick, 76, reveals.
Meanwhile, Di thinks people need to realise there will be hard times in a marriage.
"I always say to the children, 'Let me tell you, there's no such thing as the perfect marriage,'" she says. "'It's not all love and whoopsie-doo.'"
And while the pair may be in their seventies, they show no signs of slowing down.
Both still work as art dealers and agents, and find the time to entertain us with their dry commentary on Gogglebox.
"We don't do bridge or golf," Mick shares to quash any ideas they may retire soon.
As for Gogglebox, Di says they hope to stick with it.
"So long as they want us on the show, we'll be on the show!" she declares.
Surprisingly, this isn't Di's her first TV job. As a young model, Di starred in TV commercials, including one for Pepsodent toothpaste.
She reveals she was also on The Johnny O'Keefe Show and introduced musical acts when she was 15.
"That was by chance," she explains. "I was with someone and he knew Johnny O'Keefe, who said, 'I'm having this TV show. Will you be on it?' I said, 'Don't be mad!' and then the next thing, I was on it."
"Johnny O'Keefe Show to Gogglebox – a long time between gigs," Mick laughs.