The 40-year-old actor and his on/off girlfriend Laura Gallacher, 28, are set to welcome their first child into the world in just four months' time, reported Female First.
"Russell might have bedded many of the world's most stunning women but now it's all about Laura and becoming a dad," a source said.
"They have been living as a couple for the last six months and are determined to make a go of their relationship. It feels like a new chapter in their lives and the couple are enjoying every moment, including discussing baby names," the insider said.
They then set tongues wagging about a possible reunion when they were spotted looking cosy again in public in 2009.
Their chemistry seemingly fizzled out and they've lived separate lives, dating new people, until they rekindled their relationship last year in Rome.