The former 'Gossip Girl' co-stars - who split in March 2010 - reportedly spent last weekend together and sources say they couldn't keep their hands off each other.
One told Life & Style magazine: "They were eating brunch at Allswell restaurant in Brooklyn on February 11. They were seated in a corner table by the window and were kissing and making out!"
Another witness added: "I saw Ed and Jessica eating brunch at Cafe Colette in Brooklyn on Feb. 12 and they were all over each other."
Ed and Jessica ended their relationship almost two years ago but have been spotted being affectionate to each other since.
Jessica has previously said of Ed: "He's a really rad guy. He's awesome and smart and talented and adorable, and we make each other laugh."
While he was seen with Jessica before Valentine's Day (14.02.12), Ed had said he had no plans for the romantic day.
He said: "I've never done anything for Valentine's Day because there's never been anyone worth it, and I have no plans this year."