For Whom the Bell Tolls is a 1943 American war film starring Gary Cooper and Ingrid Bergman. Based on the 1940 novel of the same name by Ernest Hemingway, the film is about an American International Brigades volunteer who is fighting in the Spanish Civil War against the fascists (Wikipedia).

Virginia Grey was an American actress who appeared in over 100 films and several radio and television shows from the 1930s to the early 1980s (Wikipedia). Grey was one of the celebrities who joined John Basilone on his war bond tour in 1943 (Wikipedia). She is portrayed by Anna Torv in The Pacific.

Betty Hutton was an American stage, film, and television actress, comedian, dancer, and singer. She was one of Paramount Pictures' most valuable stars, appearing primarily in musicals. She was noted for her energetic performance style (Wikipedia). In late 1944 and early 1945, Hutton toured with the United Service Organization to the Western Pacific, visiting Guam, Saipan, Tinian, the Marshall Islands, the Gilbert Islands, and Iwo Jima. She said of the tour, "Nothing else, no other feeling in the world, could possibly compare with how I felt inside bringing joy to those young men. Everyone would gather close as we exchanged hugs and kisses. Most often, I would sing a few bars from one of my songs, or one they might request. It was difficult for those boys to believe a popular movie entertainer would crawl down into a hole to perform just for them. It wasn't crazy to me at all. I wouldn't have exchanged the precious minutes I had with those guys for anything. I did it as much for me as I did for them, but who actually received the most from the exchange is anyone's guess" (Betty Hutton Estate).

The Andrews Sisters were an American singing group of the swing and boogie-woogie eras. The group consisted of three sisters: LaVerne, Maxene, and Patricia (Patty). The sisters appeared in 17 Hollywood films (Wikipedia, The Great American Songbook). In the years just before and during World War II, the Andrews Sisters were at the height of their popularity, and the group still tends to be associated in the public's mind with the war years. They had numerous hit records during these years, some of which had service or military-related themes, including "Boogie Woogie Bugle Boy", "Three Little Sisters", and "Don't Sit Under the Apple Tree (with Anyone Else but Me)" (Wikipedia). The song Chuckler is singing in the brig, "Don't Sit Under the Apple Tree", is about two young lovers who pledge their fidelity while one of them is away serving in the war.

The Hollywood Canteen operated at 1451 North Cahuenga Boulevard in the Los Angeles, California, neighborhood of Hollywood between October 3, 1942, and November 22, 1945, as a club offering food, dancing, and entertainment for enlisted men and women, who were usually on their way overseas during World War II. Even though the majority of visitors were US servicemen, the canteen was open to allied countries as well as women in all branches of service. Their tickets for admission were just their uniforms, and everything at the canteen was free of charge. The canteen was co-founded by actors Bette Davis and John Garfield (Wikipedia). Side note: John Garfield was also one of the celebrities who joined John Basilone on his war bond tour (Wikipedia, Raritan Online).

(You can view some photographs taken during the club's operation here [via Historic Hollywood Photographs])

Rita Hayworth was an American actress and dancer. She is one of the most renowned actresses of the Golden Age of Hollywood, and was the second top pin-up girl for GIs during World War II, after Betty Grable (Wikipedia).

Side note: While her most famous film, Gilda (1946), was in release, it was widely reported that an atomic bomb that was scheduled to be tested at Bikini Atoll in the Pacific Ocean's Marshall Islands would bear an image of Hayworth, a reference to her "bombshell" status (Wikimedia Commons). Although the gesture was intended as a compliment, Hayworth was reportedly deeply offended at the sentiment.

Betty Grable was an American actress, dancer, model, and singer. Throughout her career, Grable was a celebrated sex symbol. Her bathing-suit poster made her the top pin-up girl of World War II. The photo was later included in Life magazine's project "100 Photographs That Changed the World" (Wikipedia).

Below are Rita Hayworth's most famous pin-up and Betty Grable's famous pin-up:

The photo of Betty Grable in H Company's tent appeared in the August 1942 issue of Esquire magazine:

Mae West was an American actress, singer, comedian, screenwriter, and playwright whose career spanned more than seven decades. Recognized as a prominent sex symbol of her time, she was known for portraying sexually confident characters and for her use of double entendres (Wikipedia). During World War II, Allied aircrews called their yellow inflatable, vest-like personal flotation devices "Mae Wests" partly because, when inflated, the wearer resembled the actress's buxom appearance (Wikipedia).

Mr. Lucky is a 1943 romance film starring Cary Grant and Laraine Day. The film is about an attraction between a shady gambler and a wealthy socialite in the days prior to the United States entering World War II (Wikipedia).

Marlene Dietrich was a German-born American actress and singer whose career spanned nearly seven decades (Wikipedia). She renounced her German citizenship in 1939, and when the US entered World War II in 1941, she was one of the first public figures to help sell war bonds (Wikipedia). Dietrich went on two United Service Organization tours in 1944 and 1945. She traveled first to North Africa and Italy, where she was the first entertainer to reach rescued Allied soldiers in Anzio, and then later to France and Germany, with this second tour lasting 11 months, beginning just on the heels of D-Day. Her performances in the now-famous USO Camp Shows involved singing, dancing, and a comedy routine with a musical saw, and she usually left troops in fits of laughter. She fought off bouts of influenza, slept in tents, and suffered from frostbite, but in the end, Dietrich put on more than 500 performances for Allied troops throughout the war, many of which were on the front lines. When asked why she risked her life to support American soldiers, she responded, “aus Anstand – Out of decency” (USO).

Rita Hayworth was an American actress and dancer. She is one of the most renowned actresses of the Golden Age of Hollywood, and was the second top pin-up girl for GIs during World War II, after Betty Grable (Wikipedia). Nix's comment about Hayworth's marriage is likely a reference to her marriage to filmmaker and actor Orson Welles, whom she was married to from 1943 to 1947. This is also likely an oversight by the show's writers, as the scene takes place in 1945, and a marriage that happened two years prior would probably not be breaking news.

Abbott and Costello were an American comedy duo composed of comedians Bud Abbott and Lou Costello, whose work in radio, film, and television made them the most popular comedy team of the 1940s and 1950s, and the highest-paid entertainers in the world during World War II (Wikipedia).

Seven Sinners is a 1940 American romantic drama film starring Marlene Dietrich and John Wayne. The film is about a torch singer who wows a Navy officer and his shipmates at a South Seas cafe (Wikipedia).

John Wayne was an American actor who became a popular icon through his starring roles in films that were produced during the Golden Age of Hollywood, especially in Western and war movies (Wikipedia). He also notoriously did not serve during World War II, even though many of his contemporaries did. There are many reasons given as to why Wayne did not enlist, including but not limited to: his age (he was 34 years old at the time of Pearl Harbor), his 3-A deferment (family deferment), an injury he suffered in college, his unwillingless to put his film career on hold, and his infamous affair with Marlene Dietrich he allegedly did not want to give up. The most common reason given is that the studio he was contracted under, Republic Studios, allegedly threatened to sue him if he enlisted. The studio also reportedly intervened in the Selective Service process and requested Wayne's exemption from the draft (Wikipedia). On the other hand, arguably more bankable and more famous actors, such as Clark Gable and James Stewart, enlisted for combat despite pressure from their respective studios not to do so. No matter how much of not enlisting Wayne was personally responsible for, and how much guilt he felt after the fact, he was reportedly not popular with US servicemen during World War II, and he toured with the USO for about three months in 1944 (Slash Film).