[[quoteright:244:[[Webcomic/StickyDillyBuns http://static.tvtropes.org/pmwiki/pub/images/oldfriend_sdb_4692.png]]]]
Someone knocks on the door of your [[FriendsRentControl overly spacious apartment]]. It's an Old Friend from childhood, or an old college roommate -- someone you knew long ago but lost touch with. Maybe he just stopped to say hi, or maybe he needs to bunk down at your place, or maybe he wants to share a holiday with you. He is more wild and crazy than you. You may be reluctant to join his hijinks at first, but now that he's around, you start joining in.

This can be the premise of a work or a series. Think ''Theatre/TheOddCouple'' or ''Series/{{Supernatural}}''.

If the Old Friend messing with your life isn't part of the premise, then StatusQuoIsGod will eventually have your friend leave, or you give him the boot. You will likely be unhappy; there's more than even odds he will be, too. The visit of the Old Friend will leave you wondering how little he's changed and how much you have. Or, on occasion, vice versa.

ToxicFriendInfluence is when this friendship is really bad for you; expect AnAesop about leaving the past behind you, often with the main character recalling that this is why they lost touch in the first place.

In sufficiently recent works, the Old Friend is likely to be a NewAgeRetroHippie.

Compare BeleagueredChildhoodFriend. Not to be confused with IWantYouToMeetAnOldFriendOfMine, but can overlap. Contrast OldFlameFizzle, discovering that the friendship (instead of the love) is gone.
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!!Examples:

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[[folder:{{Anime}} and {{Manga}}]]
* Parodied on ''Manga/SayonaraZetsubouSensei'' with a character in love with all things old-fashioned who claims to be an old friend of the title character's. [[spoiler: It turns out that they were friends for just one day in elementary school; it's a Japanese pun]].
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[[folder:Film]]
* A darker example occurs in ''Film/TheThirdMan'' -- the main character, Holly Martins, goes to post-WWII Vienna to meet up with an old friend, who [[spoiler: ends up having become a child-killing criminal, and whose actions turn Holly from a jovial and semi-innocent guy into a severely depressed one]].
* In ''Film/KissKissBangBang'', Harry is reunited with childhood friend/crush Harmony at a Christmas party. True to this trope, her appearance heralds [[HilarityEnsues a whole lot of trouble for Harry]].
* ''Film/TheBangerSisters'' has Creator/GoldieHawn arriving to bust strait-laced farmer groupie friend Creator/SusanSarandon out of a rutt she didn't know she was in.
* ''Film/RudeAwakening'', a 1989 film starrring Cheech Marin and Eric Roberts as two former radicals who have been hiding out in the jungles of CentralAmerica from the government, returning to the US to discover that their friends have sold out.
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[[folder:Literature]]
* In Creator/DanAbnett's ''Literature/GauntsGhosts'' novel ''Blood Pact'', an old friend of Gaunt's from school is a major character -- although it is inverted, with Gaunt turning his life upside down.
* The setup for Creator/PGWodehouse's ''Love Among the Chickens''.
* In ''Franchise/TheHitchhikersGuideToTheGalaxy'', this is basically the role that wild and crazy quasi-hippie Zaphod plays to his ever-so-slightly more down-to-Earth "semi-cousin" Ford.
* Gandalf in both ''Literature/TheHobbit'' and ''Literature/TheLordOfTheRings'' drops by the protagonist's house and gets him into an adventure.
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[[folder:Live Action Television]]
* ''Series/{{Scrubs}}'' uses this a lot:
** J.D. and Turk's old college buddy Spence, played by Ryan Reynolds, comes to visit. They envy Spence because he gets paid more money, works fewer hours and gets to drink in his time off. [[LongLostUncleAesop His whole purpose]] in the episode is to take them out and encourage them to party like the old days; they drink while on call and then have to deal with the consequences.
*** Spence even gets a WhatTheHellHero moment when they tell him about the verbal thrashing they went through from Cox the next day.
---> '''Spence''': You didn't tell me you were on call... Hey, you know, I have a presentation to give tomorrow. Ask me if I want to go out drinking tonight.
---> '''Turk and J.D.''': ''(sheepish murmuring)''
---> '''Spence''': No. '''I have a presentation'''.
** Turk's brother Kevin turns up, constantly trying to be a bundle of fun and energy to mask up his unhappiness with his divorce. He drags Turk out with him, making Turk realize that he needs to make time for his brother, even if his wackiness is annoying, because Kevin needs the emotional support. Doing so, however, causes problems in Turk's relationship with his girlfriend Carla, so actually [[BrokenAesop Turk would have been better off saying no to Kevin]].
** J.D.'s older brother Dan shows up in several episodes. His lack of maturity and responsibility in comparison to his younger brother is highlighted in a variety of ways, though each brother usually ends up learning something from the other by the end of each of Dan's appearances.
** Elliot's sorority sister Melody comes to visit. She still acts as wild as she did when the two were in college together, and this is contrasted with how much Elliot feels she has changed over the years.
* ''{{Friends}}'' has "Gandalf" (because [[StealthPun he's the Party Wizard]]) who is never seen but is described as exactly having this effect. When he fails to get into town for a planned weekend of fun, the guys try to replicate the results without him and find they can't because they've grown up and their tastes have changed.
* ''GreenAcres'' used this trope when Lisa had relatives visit. In one episode, her mother came and the entire town turned out to welcome her.
* One episode of ''Series/HowIMetYourMother'' is dedicated to the phenomenon of "[[PerfectlyCromulentWord Revertigo]]", whereby meeting an old friend temporarily turns you into the kind of person you were when you knew them.
* Done repeatedly on all the Series/{{CSI}} series. Usually one offs, but Sam Braun recurred and was revealed as Catherine's dad.
* Mike Franks played this role at times on ''{{NCIS}}'', usually turning up in time to bring a case to Gibbs's attention.
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[[folder:Western Animation]]
* In an episode of ''WesternAnimation/{{Daria}}'', Jake and Helen's old hippie friends come stay with them for a weekend. The friends are still living the hippie lifestyles, and at first Jake and Helen try to rekindle with their hippie roots. But eventually their friends reveal how weary they are of the hippie life and instead decide to adopt a more modern lifestyle.
* Inverted and subverted in the FiveEpisodePilot of ''WesternAnimation/ChipNDaleRescueRangers''. Inverted in that Monterey Jack is the Old Friend of Geegaw Hackwrench, who brings along Chip and Dale to drop in unannounced at Geegaw's home and enlist his help on the case they're investigating. Subverted when revealed that he disappeared sometime prior to the series, leaving his daughter Gadget to join the hijinks--and the cast--instead.
* ''WesternAnimation/MyLittlePonyFriendshipIsMagic'': In "Griffon the Brush Off", Rainbow Dash's old friend Gilda (a griffon she met at Junior Speedster Flight Camp) comes to Ponyville to visit. When she's not hanging out with Rainbow, Gilda displays a mean streak: she steals an apple from a produce stand, scares Granny Smith, and bullies Fluttershy until she bursts into tears and runs away. When Pinkie Pie tries to turn the situation around by throwing a welcome party for Gilda, the griffon lashes out at the other ponies, calling them dweebs and insulting Pinkie as "Queen Lame-o", and tries to get Rainbow to leave the party with her. Disgusted with Gilda's rude and selfish behavior, Rainbow tells her to go find some "new cool friends someplace else", and Gilda storms out, ending the friendship.
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