The Britain's Got More Talent presenter was recently unveiled as host of a new pilot episode of the classic quiz show, originally fronted by Roy Walker from 1986 to 1999.
Mulhern said that he mostly enjoys presenting programmes that are aimed at families.
"Britain's Got Talent and More Talent are great to be part of but I've always wanted to do a show that is really family-oriented," he told The Sun.
"Kids of all ages can watch Catchphrase and have a guess at it. It couldn't be better for me. I'm over the moon to have been chosen to do it.
"I don't think it's a bad thing it has taken me a long time to get here. I've learnt my trade and made all my mistakes on Britain's Got Talent."
Mulhern added that he plans on using one of Walker's classic lines on the show, while also trying to create some of his own.
"I'll use, 'Say what you see', because it's so synonymous with Catchphrase.
"But I'll get it out of the way early and then move on to something different. 'See it and say it' perhaps, or 'It's on the screen, what does it mean?'
"I've been lying in bed thinking about my catchphrases ever since I signed up for it. It's hard because you never want to be compared but it is always going to happen."
The original format of the show will remain in the revived version, although the show will have new 3D graphics and a new concluding game.
Stephen Mulhern's pilot will be filmed in London on August 27.