Paul Rudd turned 42 today (no, seriously, we know he doesn't look it), and celebs like Kristen Bell, Mark Ruffalo and even Katie Couric took to the Twitterverse to celebrate. They weren't just sharing the Rudd-love, though, they were also spreading the word about the birthday gift Paul asked for from his friends and fans: donations to the American Cancer Society. As if the cause weren't good enough to begin with, Kristen shared the extra incentive for fans to make a donation, tweeting, "Happiest Birthday Paul Rudd! http://tinyurl.com/66q44n7 Donate $26 to Paul's ACS project & you'll be signed up 2 win a live iChat w/ him!"
One star who has really earned a slice of Paul's birthday cake is Sara Rue—who, after losing 50 pounds, revealed this week that she donned a bikini for the first time ever. Sara tweeted her joy, saying, "Omg! I still cant believe it- FIRST BIKINI EVER ! 
RT @peoplemag: Hubba hubba! Sara Rue shows off her new bikini bod http://bit.ly/h1rMvJ." Other celebs also sent Sara supportive shout-outs, like pal Ashley Benson, who tweeted, "@SARARUEFORREAL ahhh sara you look absolutely STUNNING!!! yayy so happy for you!!! xoxo."
Check out the rest of Wednesday's best tweets from the stars, including one celeb's "secret" for getting noticed by casting directors. Follow us @hollywoodcrush to get even more celebrity and pop culture news around the clock!
@DavidArchie My voice sounds like a frog after suffering from allergies this weekend. Oh man haha.
-David Archuleta, Singer
@breagreant At Forever 21 playing "Is this a dress or a shirt?"
-Brea Grant, Actress ("Heroes")
@blakeshelton Wow!! Dreams do come true... I'm on top of Rhianna and under Katy Perry!!
-Blake Shelton, Musician
@NateHartley There's a fine line between looking wealthy and looking homeless when wearing a robe.
-Nate Hartley, Actor ("Zeke and Luther")
@alisonbrie Last night I dreamt that Matt Damon slept over & in the morning all he wanted to do was watch Community. Best. Dream. Ever. #sovain
-Alison Brie, Actress ("Community," "Scream 4")
@NathanFillion Dear @RobinofLeyLines, Bottle your amazingness. Then I will buy that bottle and drink from it. Your friend, Nathan
-Nathan Fillion, Actor ("Castle")
@RachaelLCook Wanna meet casting directors?! Don dog hair covered polarfleece & moon around the bakery section of your local market. Works every time!
-Rachael Leigh Cook, Actress ("Psych")
@ninadobrev Need to do some retail therapy!
-Nina Dobrev, Actress ("The Vampire Diaries")
@zachbraff @donald_faison thanks c-bear. I miss your soft touch. Don't forget to lotion your elbows; you hate it when they get ashy...
-Zach Braff, Actor ("Scrubs")
@spencerpratt World hunger - POW, solved. Oh Spencer, is there nothing you can't do?
-Spencer Pratt, Reality Star ("The Hills")
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