Happy 21st birthday, Taylor Swift! While we're sure the Grammy-winning singer (pictured) is spending her day with her adorable beau Jake Gyllenhaal, she was getting plenty of love around the Twitterverse. Katy Perry told her fellow pop star, "@taylorswift13 happy 21st gorgeous!" and pal Selena Gomez had a wish for her, too, as she posted, "Happy birthday @taylorswift13 !!!!!!!! I love you so much!!"
Taylor isn't the only one with something to celebrate this season, though. Actress Kristen Bell will get to spend time with her boyfriend, Dax Shepard, over the holidays, and it can't get here a day too soon! Dax posted to his lady over the weekend, "I'll sing the "Birdsong" WHILE making tiki marsala if you just get your a** home already!" and Kristen sweetly responded to her man today, "1 u don't have 2 do a thing 2 convince me 2 come home-I'm countin the days! Wonder if ur as cute as I remember...prbly moreso 
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Check out the rest of Monday's best tweets from the stars, including Ashley Greene getting up bright and early for "Breaking Dawn," while Quinton Aaron stops by the set of "One Tree Hill"! Follow us @hollywoodcrush to get even more celebrity and pop culture news around the clock!
@msleamichele So much fun at the Style Awards last night! Got to see my boys @chriscolfer and @frankenteen! Great way to end an awesome weekend:)
-Lea Michele, Actress ("Glee")
@ashleymgreene Guess I better get used to early morning set calls good-morning everyone!
-Ashley Greene, Actress ("Breaking Dawn," "Eclipse")
@sophiabush My dear friend Quinton is here to play on set !! So excited to have him here. Some major OTH/Blind Side crossover lo... http://say.ly/UzN5AN
-Sophia Bush, Actress ("One Tree Hill")
@coltonlhaynes Heading to the table read for ep. 108 with no clue what's gonna happen, they keep it so secretive! I hate surprises. #MTVteenwolf
-Colton Haynes, Actor ("Teen Wolf," "The Gates")
@jamiebower I JUST SNEEZED ON MY OWN FACE. MOST DISTRESSED BY THIS.
-Jamie Campbell Bower, Actor ("New Moon," "Harry Potter and the Deathly Hallows")
@nolan_gould I learned ice skating is alot of fun! Falling, not so much. No shorts for me for awhile.
-Nolan Gould, Actor ("Modern Family")
@jaimiealexander why must every song on the radio be a crappy sappy love song? where's the death metal?
-Jaimie Alexander, Actress ("Love and Other Drugs," "Kyle XY")
@lucyyhale do you ever see someone so hot sometimes and it drives you so crazy that you wanna punch them? or is it just me...
-Lucy Hale, Actress ("Pretty Little Liars")
@oliviawilde Here's a thought, if you have a loud, uncontrollable, hacking cough, maybe skip the movie theatre tonight. Mull it over.
-Olivia Wilde, Actress ("TRON: Legacy," "House")
@sethmacfarlane If Miley Cyrus had just hit that bong dressed as Hannah Montana, no one would’ve known it was her.
-Seth MacFarlane, Writer, Actor ("Family Guy")
** Hollywood Crush Twitter