The comic star`s paternal instincts were kick-started after he was asked to be godfather to his friend`s one-year-old twins, and the boys have taught him about the joy of nurturing and care.
When asked by TV host Ellen DeGeneres if he and his pop star wife are planning a family, Russell replied: "I would like one. I love those little babies in the beginning. They`re so lovely in that bit. Me and Katy are godparents to two twin boys. They`re called Sam and Donovan.
"At first they were boring. They were just essentially little fluid factories, generating fluids - no regard for what I was wearing.
"Now, they are interesting. They smile and look at me and wonder - I`m just observing them like I-m a scientist."
Russell - who married Katy in October 2010 - takes his role as godfather seriously, and insists he will be responsible for their "spiritual growth".
He added: "I can learn from them. Me and Katy are their godparents, which means we`re responsible for their spiritual growth. Should be interesting."
Katy recently revealed she is taking a year off now her `California Dreams Tour` has ended to concentrate on having a baby with her husband.
She said: "I would love to have children. I think that`s one of the reasons you get married. Especially to the person that you marry. You think, `That person is going to be a good partner, a good parent.`
"But I`m not sure it`s yet. We`ll see, you know."
In his interview for `The Ellen DeGeneres Show`, Russell also brushed off rumours that their marriage was in trouble.
He joked: "There are always rumours aren`t there? In the end you have to just not engage with Internet technology, which is difficult because of a lot of the nude women websites I quite enjoy.
"But they`ve had to go. I`ve treated the whole Internet now like it`s a wicked little liar. Yeah. I am really happily married."