Just This Once is a 1952 American romantic comedy film directed by Don Weis and starring Peter Lawford, Janet Leigh and Lewis Stone.

Judge Coulter, executor of his estate, puts Mark's finances in the hands of a penny-pinching lawyer, Lucy Duncan.

He still extravagantly tips a busboy $10 after a 50-cent lunch or charters a plane to fly off to Paris without a thought as to his financial situation.

Lucy shuts off his access to funds, causing an angry Mark to barge into her personal life, moving into her apartment and upsetting her routine.

Now in love, Mark and Lucy must hold off making plans for the future because the Naval Reserve has called him to active duty.