British playwright Sir Tom Stoppard is set to walk down the aisle for a third time, according to a U.K. report. The Oscar-winning Shakespeare in Love screenwriter reportedly proposed to Sabrina Guinness, heiress to the Guiness brewery fortune. A source tells Britain's Mail on Sunday, "Tom is the great love of Sabrina’s life and she could not be happier. She thinks he is the kindest, most wonderful man in the world and they are both beyond happy and thrilled." Guiness was once romantically linked to British royal Prince Charles before he wed Princess Diana. Stoppard, 76, has been married twice before to Josie Ingle and Miriam Stoppard.