MACFarlane split from the Game Of Thrones beauty earlier this year (13) and is now dating Pitch Perfect actress Knapp, who has a two-year-old daughter Kailani with ex-boyfriend Ryan Philippe.
A source tells E! News, "It's been going on for a little while. It's very casual but they are hanging out and he is having fun with her. Alexis' star is on the rise (and Seth) thinks she's really talented."