The New Girl star went public with her new beau at the Magic Mike premiere afterparty, Us Weekly reports.
Linden, who has worked on movies such as Dear John and 10 Years, was allegedly spotted holding hands with Deschanel at the event.
"Jamie's a really nice guy," a source said. "He's funny, and a little geeky... He's into her!"
Deschanel was previously married to Death Cab for Cutie frontman Ben Gibbard, but the couple split last November and Deschanel filed for divorce earlier this year.
She was later linked to Russell Brand, but denied rumours that the pair had exchanged flirtatious text messages.