Taylor Lautner hit the gym in LA on Sunday to work out those newly 19-year-old muscles. The hot young actor just celebrated his birthday with an early Valentine's date alongside Abduction leading lady and rumored flame Lily Collins last week. He's currently home in California on a break from shooting Breaking Dawn, as production moved from Louisiana to Vancouver and is already under way up North. The cast is well acquainted with the Canadian city after shooting New Moon and Eclipse there in the past, so it's a bit of a homecoming for the crew. Taylor's Twilight costars all took advantage of their downtime in different ways — Robert Pattinson kicked off press duties for Water For Elephants and Kellan Lutz enjoyed NYFW while Ashley Greene partied into her 24th year in Vegas with Joe Jonas and Kristen Stewart tended to her mysteriously injured wrist. Taylor maintains an impressive physique that helps him avoid hurting himself doing his many stunts for the saga and all the other big money projects he keeps lining up, though Kellan also has some impressive shirtless abs to show for all his time spent lifting weights.