AceShowbiz -

Gwyneth Paltrow and Chris Martin attended the screening of "Hector and the Search for Happiness" together at UA Theater in East Hampton on July 28. Later in the evening, the estranged couple was reported getting "very flirty" at after party of the movie screening at Serena & Lily in Wainscott.

According to New York Daily News, Chris sat together with his mother-in-law, Blythe Danner, who previously also attended Simon Pegg's movie screening, while Gwyneth was standing near them. The frontman of Coldplay and Blythe were chatting with other guests, including director Peter Chelsom, Nacho Figueras, Tracy Anderson, Cristina Cuomo, Joey Wolffer, Kyle DeWoody, and Lily Kanter, co-founder of Serena & Lily.

A source told the site, "Chris was sitting and Gwyneth was standing up talking to people. She looks very relaxed and happy. They looked very happy in general. They were very warm to each other."

The source revealed that Chris later joined the "Iron Man" actress to chat with the guests. "They were chatting and she was being very flirty with him. She pulled something out of his hair and ruffed it up a little. They were very cute," said the source.

"Then Nacho Figueras and his wife Delphina went up to Gwyneth and Chris and they were all chatting and laughing," the source added, "Paltrow even used Chris' phone and took a pic of Nacho and Chris together. They were all laughing and Gwyneth was rubbing Chris' shoulder affectionately. They seemed like the cutest summer couple, very flirty and fun-loving. You would hardly know that they had recently broken up. It looks more like they just started to date."

Another source told PEOPLE, "I don't know what's going on with them but they seem really happy."