The actor and his wife Liz Marsland already have two children, daughter Marnie and son Milo, and now they've got two more on the way.
In an interview and photoshoot with Hello!, the couple have announced that they are expecting twin boys in May.
"We've already got the best of both worlds with Marnie and Milo, so I didn’t mind either way, but finding out we're having sons is amazing," Kelvin said.
"It was the best day of my life. It was a moment of complete disbelief. I’ve never felt joy like it."
"I felt every single emotion under the sun," Liz added. "First, there's double the worry. I thought about things like breastfeeding, how is that possible with two? How do you pick up two babies at the same time? I felt all of this in the space of 30 seconds.
"Kelvin was saying it's a miracle, and I was thinking: 'How are we going to do this?' But now we can't imagine it any other way. We feel so lucky."
We're not sure how Kelvin is going to find the time to raise twins, as the couple run a farm, which is a pretty intense lifestyle. He also does a lot of motor racing and is making his National Theatre debut in Jack Absolute Flies Again, with rehearsals said to begin just weeks after Liz is expected to give birth.
Emmerdale airs weeknights at 7.30pm on ITV and streams on the ITV Hub.