Dianne Wiest could easily pass as Renee Zellweger’s mother.
a35362, I don’t see the Meryl/Renee thing, but many people have noticed the Jewel / Renee Zellweger resemblance. Renee has better teeth; that’s the only way I can tell them apart.
Lena Olin and Jennifer Garner. 
In a recent episide of Scrubs, Tom Cavanaugh of Ed played Zach Braff’s older brother. They must have written the part for him, because the resemblance is pretty good.
I remember reading a story about Vicki Lawrence being cast on The Carol Burnett Show because she looked like she could be Carol’s sister. I can kind of see this.
Patrick Swayze and Kurt Russell (brothers)
Nicolas Brendan and Bruce Campbell (son/father)
My friend swears Ethan Hawke and Sean Astin look alike but I cannot see the resemblance
Renee Zellweger and Joey Lauren Adams (sisters)
Claire Forlani and Jennifer Garner
Catherine Zeta-Jones and Jill Hennessy
I know its a minor spoiler but some people haven’t seen this great movie so I won’t ruin it. James Garner and Mel Gibson were completely believable as father/son team in Maverick
agree with Redford/Pitt and Ricci/McGowan
Hunter Tylo and Liv Tyler could be mother/daughter.
Dylan McDermott and Aidan Quinn could be brothers.
Tommy Lee Jones and Josh Hartnett as father/son.
Joey Lauren Adams (from Chasing Amy) and Renee Zellwegger could play sisters.
At first, I thought Jewel Staite was Jewel Kilcher.
i didn’t see anything about dead or alive, so i’ll nominate kelsey grammer and orson welles.
John Cusack and Paul Rudd, who is currently playing Phoebe’s boyfriend on Friends
Ted McGinley and Aaron Dozier, who played the same roll in Better off Dead that Ted McGinley played in Revenge of the Nerds
HH, I don’t think they look alike (not by 200 lbs or so) but they sure SOUND alike. Close your eyes and you would never know which one was speaking.
Mentioned in a previous thread:
Tom Cruise and Peter Facinelli (of Fastlane)
Good one! Have you ever seen youn TLJ in The Paper Chase?
Also:
-
Matt LeBlanc could play Sylvester Stallone’s son.
-
Jada Pinkett-Smith could play James Earl Jones’ daughter or grand-daughter.
-
Angela Basset and Lynn Whitfield could play sisters.
-
The Lowry twins (from Sister Sister) could play Gregory Hines’ duaghters.
What?
Meg Ryan and Sarah Jessica Parker
on what planet?!?!?
When I saw Hugh Jackman and Meg Ryan in Kate & Leopold, they looked like Matthew Broderick and Sarah Jessica Parker’s older siblings to me.
Wow. You are not kidding there…
Don’t know if I can agree about Scully…but in this shot she does look a tad of Julianne Moore from “The Shipping News” http://www.josite.hey.nu/jo1.jpg.html
Timothy Dalton and Patrick Stewart. Always freaks me out. 