And it seems to have worked – so far, at least.
The 29-year-old racing driver has been on a winning streak and hopes it will continue on Sunday by lifting the F1 trophy in the final race of the 2014 season in Abu Dhabi.
But according to Natalie, there's another reason why Lewis - who is dating former X Factor judge and Pussycat Dolls singer Nicole Scherzinger – is getting tactile with her growing bump: he's feeling broody.
Which is ironic - because Nicole's desire for a baby was believed to be the reason why the couple broke up for a while in 2011.
Natalie told the Mirror: "When I told him I was pregnant he was incredibly supportive and happy for me. All the drivers were.
"But Lewis has this thing where he rubs my bump before every race, and calls it his 'Lucky Buddha'.
"When I told him I was off on maternity leave, he was like, 'No, you can't go. I've still got three more races'.
"He has been getting really interested in my pregnancy. He is always asking me things like, 'Is it beautiful having a baby?'
"I'm always winding him up, asking when he's going to propose to Nicole, telling him to get on with it.
"He's a Christian guy and she's a Christian. I can't imagine they won't get married and have a family of their own.
"I think he wants to."
Natalie, 36, who has worked for Sky Sports as their chief pit-lane reporter since 2012, is married to Welsh TV director Owain Walbyoff, 32.
Her baby is due on January 11, but she is keen to return to work as soon as possible.
Her Sky bosses have even offered to build a portable creche so she can continue to travel the F1 circuit.