Channing Tatum and Jenna Dewan-Tatum
01/27/2013 at 01:00 AM EST
gives his all to every project he works on – and the same will be true for fatherhood.
"That [will] be the biggest role of my life. I hope I don't screw that one up," Tatum said humbly while promoting his latest movie, Side Effects
, in Los Angeles on Saturday.
Tatum and wife Jenna Dewan-Tatum, both 32, announced in December that they're expecting their first child
The actor says he's "really, really excited" about becoming a dad and is looking forward to some quality family time once the baby is born.
"I hope to slow to down a little bit when the little person comes into the world," he says.
As for his charmed life of late, PEOPLE's Sexiest Man Alive
attributes it to good fortune – and a lot of work.
"Look, I've been lucky," he says. "I've said it before, we work so hard on every single [movie] and you never know which ones are going to work and which ones aren't. ... I think it's just, you've got to keep doing stories you love and characters that you love."
, directed by Steven Soderbergh and also starring Rooney Mara
, Catherine Zeta-Jones
and Jude Law
, opens Feb. 7.
Reporting by GABRIELLE OLYA