The Queen's 23-year-old granddaughter attended a London screening of the "Meet the Parents" sequel with rugby player boyfriend Mike Tindall, 26, the Daily Mail reported.
Their attendance at the movie about meeting prospective in-laws undoubtedly will add fuel to a recent report that Tindall proposed in November, the newspaper said.
Zara Phillips, the daughter of Princess Anne and Captain Mark Phillips, met Tindall in Australia during the World Cup.
Separately, she was parked outside Tindall's home in Bath when she was given a ticket Sunday for an out-of-date car tax sticker. Police said a passerby noticed the tag that expired more than three weeks earlier on Zara's Audi S3, The Mirror reported. She and the 1.2 million other British motorists who fail to pay the tax are "irresponsible," an official told the newspaper.