The announcement to family and friends was made at P.E.I.'s New Glasgow Lobster Suppers restaurant. Cuthbert and Phaneuf, who have been dating since 2008, spend their summers on P.E.I.
The owner of the restaurant did not want to comment, saying he wants to respect the couple's privacy.
Reports on Facebook and Twitter say it was a private party for 40 people at the restaurant Sunday night.
Afterwards Cuthbert tweeted, "Happily, happily, happily, happily engaged. This has been the most amazing weekend ever."