LOS ANGELES (Reuters) – Former "Friends" star Jennifer Aniston is engaged to marry her actor and screenwriter boyfriend Justin Theroux, People magazine reported on Sunday. "Justin Theroux had an amazing birthday on Friday, receiving an extraordinary gift when his girlfriend Jennifer Aniston accepted his proposal of marriage," Theroux's representative told the celebrity magazine. Aniston's publicist Steven Huvane confirmed the engagement. Aniston, 43, and Theroux, 41, have been dating for more than a year and appeared in the comedy "Wanderlust" in February. No wedding date was announced. …