Is Ryan Reynolds ready for diaper duty?

A source tells the new issue of Us Weekly (on stands now) that the actor, 34, and Sandra Bullock, 46 -- who shared a flirty New Year's Eve together in Austin, Texas -- have grown closer thanks to her son, Louis.

"Ryan loves Louis, and Louis always smiles when Ryan's around," a source says.

Find out more about how Reynolds is leaning on Bullock since splitting with  soon-to-be ex-wife Scarlett Johansson in this week's Hot Stuff video, as explained by Senior Editor Ian Drew and Rev Run.

Also in the roundup: Details on Blake Lively's flirty night at Jeremy Renner's birthday bash, Zac Efron and Vanessa Hudgens get cozy at a Hollywood club post-split, and much more!