Paul Rudd & Reese Witherspoon Grin in Berlin

These two look they're definitely having a blast over in Germany promoting How Do You Know?.  Paul Rudd and Reese Witherspoon were all smiles as they attended a photocall for their flick, Woher weisst du, dass es Liebe ist in German, at the Hotel De Rome on Wednesday in Berlin. We're not surprised their costar Luke Wilson was absent, as the actor just became a proud papa!

OK! GALLERY: REESE WITHERSPOON & PAUL RUDD SAY "HALLO" TO BERLIN

Luke and his girlfriend Jade Duell welcomed baby Robert Ford Wilson earlier this week.

OK! NEWS: OWEN WILSON WELCOMES A BABY BOY!

Paul and Reese both arrived in Berlin yesterday. Wonder how long they'll be jet-setting around Europe?