Spencer Matthews admits that he pines for his son when the pair are apart, even if just for a few hours.
The former 'Made in Chelsea' star admits he misses Theodore - his child with his wife Vogue Williams - when he spends any time away from him.
Spencer said: "When I'm away from him for a couple of hours, I really miss him. Always thinking about him.
"Life's different I suppose, because, you know, responsibility shifts and priorities shift. I'm no longer number one, I've got to put him first."
The 31-year-old reality TV star admits that becoming a father has been the "most wonderful change" to his life and he admits it's difficult for him to describe just how much he loves his lad.
Spencer explained: "Obviously, anyone who's had a child for the first time will tell you that life is pretty different. But I think as long as you're ready for it and excited by the prospect, then it's the most wonderful change you can imagine.
"It's hard to imagine, loving someone or something as much as your son. And everyone says that to you beforehand about waiting until they arrive and how much you will love him, and you think yeah, I'm gonna love my son but it's actually, it's pretty remarkable."
And Spencer also revealed that little Theodore shares his father and mother's "mischievous" personality.
He said: "He's quite mischievous like he enjoys not doing what he's told. If you ask him to come here, he will look at you and run the opposite direction and he loves to play hide and seek. He's very playful and very adventurous. He's got great balance weirdly. Yeah, I mean Vogue and myself are quite similar. So, I suppose my traits in him also mirror hers."
Spencer has teamed up with 'Thomas & Friends' for 'Reading with Friends' to kick off the 75th anniversary celebrations of the world famous children's character.
Spencer along with Peter Andre and Harry Judd have teamed up to deliver a unique digital story showcase which features the three celebrity dads reading 'Thomas & Friends' stories which are available as videos UK YouTube channel now.