The pair bonded instantly, he said.
Labbett said, "I was walking him around the fields, taking me places … I think he's helped a lot, simply because I'm doing more activity."
He has previously spoken about the weight loss that took him from a size 5XL to XL.
"I am gradually dropping Xs off my size. I've gone from 5XL to 4XL and it looks like the next time I go shopping I'll be able to squeeze into XL underpants."
When asked how he managed to lose so much weight, Labbett - who shares a young son with his ex-wife Katie - joked that running around after a toddler non-stop might have something to do with it.
He said: "The principal thing is running around after a hyperactive toddler when nurseries have been shut. How do you keep up with them?
"I found at the end of the evening instead of going to the fridge for late night snacking, all I could do was collapse on the bed."
He and Katie, who married in October 2014, announced their split in August last year.
At the time Labbett said, "There was never any deceit on Katie's part but it's got to the point now where I realise it is better for us to go our separate ways and remain friendly."