Gretchen is a fictional character who appeared in the Hogan's Heroes episode, Top Hat, White Tie and Bomb Sight. She was played by Sigrid Valdis.
Gretchen is first mentioned in the episode by Kommandant Klink while he is talking with General Burkhlater outside his office on how to convince Colonel Hogan to reveal to them the plans for the American Norden bombsight. He mentions to the General that she is a local girl whom he has started seeing and that she and a friend of hers might be interested in coming to the dinner that they plan to hold in Hogan's honor at the Hauserhauf hotel in Hammelburg that Klink had just informed Burkhalter that Hogan has mentioned to him earlier that he has wanted to visit.
Gretchen then appears physically, sitting at a table inside the hotel, seated between Klink and a German uniformed Hogan. Also, although she is suppose to be Klink's date, she appears to be more interested in Colonel Hogan, as she and the others listens to first Burkhalter and then Hogan talk. Then she is asked by Klink to dance with him. She tells him no, saying that she is tired. But she then asks Hogan, who agrees to get up from the table with her, and then goes to the dance floor with him. As they dance, she watches Hogan dance them over to the bartender, whom she then sees him asks a question about Lili Marleen, not knowing that it is actually a part of a coded message. She then hears the bartender's reply, who thinks that it is the name of a drink, which in the process convinces Hogan that he isn't Willie, the underground agent, he is suppose to meet and warn. She then watches Hogan dance them away from the bartender which seems to peeks Gretchen's curiosity, as she attempts to strike up a conversation with him. Gretchen asks him why he has asked him about Lili Marleen and is told by him that he is taking a survey. Later, Klink appears, taping Hogan on the shoulder and asking to cut in on them. Gretchen sees Hogan happily let Klink dance with her. Gretchen then gasps as her foot is stepped on, before she unhappily starts to dance with Klink, while Hogan goes back to the table. A short time later, Hogan returns and taps Klink on his shoulder, asking him to cut in, to Gretchen's relief. She continues dancing with Hogan until he finally finds Willie. Gretchen then hears him tell her to go back to the table while he goes talk to an old friend. She does, after kissing Hogan on the mouth.
Gretchen is last mentioned at the end of the episode, after Hogan returns all of the bugs that Klink had earlier placed inside his office, claiming that it is for Klink's own good, as he might talk about Gretchen in his sleep.