Just This Once is a 1952 American romantic comedy film directed by Don Weis and starring Peter Lawford, Janet Leigh and Lewis Stone. It was produced and distributed by the Hollywood major Metro-Goldwyn-Mayer. The film's sets were designed by the art director James Basevi.

Mark MacLene IV is a millionaire playboy. He is totally irresponsible with his money, piling up $5 million in debts. Judge Coulter, executor of his estate, puts Mark's finances in the hands of a penny-pinching lawyer, Lucy Duncan.

Mark is aghast when Lucy puts him on a $50-a-week allowance. 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. She wants to quit, but Coulter doubles her pay.

Lucy has a fiancé, Tom Winters, who has held off on proposing marriage until he can afford it. Mark owns a construction company where Tom works, so secretly he plots to get Tom a huge raise. Lucy sees through the ruse. But when she learns Mark also has offered his yacht for their honeymoon, she begins to see a different side to him.

Now in love, Mark and Lucy must hold off making plans for the future because the Naval Reserve has called him to active duty. Lucy fears for his safety, but Mark says he's going to Washington, D.C., and getting a desk job where he will be in charge of Navy expenditures.

• Peter Lawford as Mark MacLene
• Janet Leigh as Lucille Duncan
• Lewis Stone as Judge Coulter
• Richard Anderson as Tom Winters
• Marilyn Erskine as Gertrude Crome
• Douglas Fowley as Frank Pirosh
• Hanley Stafford as Mr. Blackwell
• Henry Slate as Jeff Parma
• Jerry Hausner as Stanley Worth
• Benny Rubin as Herbert Engel
• Charles Watts as Adam Backwith

According to MGM records the film earned $707,000 in the US and Canada and $352,000 elsewhere, making a profit of $89,000.^[1]

• Eastern Color Movie Love #14 (April 1952)^[2]