"Keanu and Autumn have known each other for years," a close friend told the Daily Star. "In May they got together again and over the past few months, Keanu started thinking about settling down. He has spent weeks building up to going down on one knee."
Reeves had been unattached since the 2001 traffic death of his girlfriend Jennifer Syme, who gave birth to his stillborn child in 1999.
Reeves has been caring for his sister, Kim, who is battling leukemia, World Entertainment News Network reported Monday.
"They've both told pals to expect the announcement later this week," friends said. "It will just be a simple ceremony, Keanu hates fuss and attention."