Ryan Phillippe dog shelter walk tee shirt

We're not sure who's cuter -- Ryan or his new pup!

Phillippe recently told Jimmy Kimmel he adopted the German Shepard from a local animal shelter to cheer up his son Deacon one day when the 7-year-old was feeling down.

And a hot guy walking an adorable dog certainly doesn't hurt with the ladies ... but Ryan's not on the market, girls! His leading lady Amanda Seyfried's an animal lover too, so no doubt she approves of this new addition!