That's My Boy premieres in Westwood Village at the Regency Village Theatre! Stars from the movie (Adam Sandler, Andy Samberg, Leighton Meester, Will Forte, James Caan and others) are all scheduled to start walking the red carpet sometime between 5:00 p.m. and 6:30 p.m. When I called they weren't positive of the start time. I'd recommend arriving earlier to ensure a good spot to see celebrities as they arrive.
The Regency Village Theatre is located at 961 Broxton Avenue and directions can be found here.