The couple split when it was revealed that Stewart had a fling with married director Rupert Sanders.
"Robert and Stewart had dinner at the Soho House in West Hollywood Saturday night and they looked like a couple, smiling, holding hands. It was like old times," contactmusic.com quoted a source as saying.
"They were with a few other friends, two guys and another girl. They sat in the restaurant which is decorated with really beautiful lights everywhere. It's really romantic," added the source.
Although it took Pattinson, 26, some time to forgive 22-year-old Stewart for her infidelity, the source said they seemed completely besotted with each other once more.
"Both of them were dressed casually. They were laughing a lot with their friends and stayed for a pretty long time. Like from nine until past midnight. Occasionally Rob and Kristen would go outside to smoke."
"What's funny is that they acted really comfortable with each other, like none of that affair drama had ever happened. They didn't act awkward or embarrassed at all. It was great to see them back together and happy," said the source.