Moore and Willis, 24, were seen at a class at Golden Bridge Yoga on Apr. 27. Willis' boyfriend Jayson Blair joined them.
"They all did the class together, and after 90 minutes they walked out as a group," said an Us Weekly source.
This is the first time since the estrangement the pair has been seen together. Rumors surfaced after Moore's rehabilitation that all three of her daughters with actor Bruce Willis were considering getting a restraining order against her, but the orders were never filed.
"Demi and Rumer seemed very close, like they had been in the past. There didn't seem to be any tension or hard feelings between them," the source said.
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