Jake Gyllenhaal is Rad in Plaid

Jake Gyllenhaal gets casual in a plaid shirt and does some shopping in Beverly Hills on Thursday (March 26).

The 28-year-old Brokeback Mountain star threw his girlfriend, Reese Witherspoon, a bash for her 33rd birthday at his Los Angeles house on Saturday.

Jake‘s sister, Maggie, stopped by with her longtime love Peter Sarsgaard and their daughter Ramona. Robert Downey Jr. and wife Susan also came by for the party!

10+ pictures inside of Jake Gyllenhaal looking rad in plaid…