Referring to the film as The Out-of-Towners, the 15 Apr 1962 NYT announced that producer Martin Manulis, writer Tad Mosel, and director Delbert Mann were collaborating on the forthcoming original drama. Production was not set to begin until the following spring, in Hollywood, CA. According to the 28 Oct 1963 NYT, the story was based on Mosel's 1957 television presentation of the same name, which aired on "Studio One," a dramatic anthology series that ran on Columbia Broadcasting System (CBS) from 1948-1958. The adaptation marked Mosel's first theatrical screenplay.
       The 23 Apr 1962 DV reported that Manulis-Mann Productions had been formed to complete the independent picture, although the onscreen producing company credit was listed as Out-of-Towners Co.
       On 27 Jul 1962, DV announced that Deborah Kerr was signed to star, and Robert Mulligan was named as director, but neither remained with the project. At that time, locations were set for Hollywood and New York City. On 23 Aug 1962, DV noted a Jan 1963 start date. However, production was delayed, and the 5 Mar 1963 issue indicated that Glenn Ford was in talks to star. Anne Bancroft and Geraldine Page were in consideration to co-star. Page ultimately won the role.
       The 12 Dec 1962 DV stated that Manulis would soon join Four Star Television as head of their newly formed theatrical production department. The Out-of-Towners was set to be one of their first releases. On 20 May 1963, DV reported that the independent film would be released by Warner Bros. Pictures. An Oct 1963 start date was anticipated, and Delbert Mann was attached to direct.
       The 10 Sep 1963 DV announced that filming was set to begin on location at Grand Central Terminal in New York City on 30 Sep 1963, before the production returned to the Paramount-Sunset Studios in Hollywood, due to overflow at the Warner Bros. Studios in Burbank, CA. However, the 20 Sep 1963 issue stated that principal photography would begin on 2 Oct 1963 at New York City's Penn station, where production would continue for one week before relocating to Hollywood. The 7 Oct 1963 DV confirmed that the crew had returned to CA.
       The 16 Aug 1963 DV named Michael Lindsay-Hogg as Manulis's assistant. Various items published in Oct 1963 and Nov 1963 issues of DV added Ralph Manza, Peter Ford, Allyson Ames, and Ronnie Knox to the cast.
       On 15 Apr 1964, Var noted that production had been completed, and indicated that the picture was produced by Four Star Television in association with Martin Manulis Productions and Biography Productions, with Warner Bros. attached as financiers.
       The 20 Aug 1964 DV announced the title change to The Big Weekend. Three weeks later, the 11 Sep 1964 issue reported that the title had been changed again, to Dear Heart, after Jack L. Warner heard the original song of the same name, written for the film by Henry Mancini, Jay Livingston, and Ray Evans.
       The 30 Nov 1964 LAT listed 3 Dec 1964 as the Los Angeles opening date at the Hollywood Paramount Theatre, where the film was scheduled to run for three weeks for Academy Award consideration before its national release. The 17 Dec 1964 NYT announced that the official premiere would be held in Mar 1965 at New York City's Radio City Music Hall. The 1 Mar 1965 DV confirmed a 6 Mar 1965 premiere date, and reported that the Music Hall was undergoing a five-day renovation to prepare for the event, noting that both the closing and the theater's collaboration with a major motion picture company for a film premiere were rare occurrences.
       Film reviews were mostly negative. The 2 Dec 1964 DV praised Mann's direction, but complained that the story was "lackluster." The 8 Mar 1965 NYT similarly deemed the picture "stale, dull and humorless."