POTW: Justin Bieber, Lady Gaga, Christina Aguilera, Chris Brown
Chris Brown says 'deuces' to dark hair and surprises everyone by dying it blond.

Here's our round-up of singers', rockers' and rappers' 20 coolest and funnest tweets from the past seven days. Be sure to tag @billboarddotcom to your favorite music retweets (and don't forget to follow us!)

@RealTalibKweli: RIP DJ Megatron. Gone way too soon. Peace to his family.
ChrisBrown: I wanna thank all of my fans for making my album number 1 in the country!! I love you! We did it
@EstelleDarlings (Estelle): Abercrombie and fitch have a padded bra aimed at 9 year olds. Uhmmmmmmmmmmmmmmmm #denied. #thashowifeel let em be kids!
@LupeFiasco: for those who say i dont put out free music or question my love for my fans...take this as a peace offering or a STFU whatever fits you haha
@LadyGaga: I woke up to chicken and waffles in bed, pink tulips, + little monster bday videos. I love you! I was #bornthisday but u were #bornthisway.
@yelyahwilliams (Hayley Williams): happy birthday to miss gaga. i like your new dark bangs. they look bad ass.
@ChrisColfer: Watching the news. How are animals still escaping from the zoo? We have hovercrafts but we can't invent a monkey-proof lock?
@TheReadySet: "POISONOUS COBRA ON THE LOOSE: PEOPLE WERE A LITTLE NERVOUS" - best tv headline I've ever seen.
@SteveMartinToGo (Steve Martin): Phone rings. Caller ID: Bronx Zoo. I put on King Tut hat, ready for action. It's the snake. Hard to hear. Lots of hissing on line.
@AndrewWK: PARTY TIP: True wealth isn't about how much money you have. It's about your ability to wake up, rock out, and party really hard.
@PeteWentz: most times when ppl ask if im pete wentz and i say no its cos i dont feel like i am at the time. #100factsaboutme
@realwizkhalifa: when u live this life, sometimes u wake up juss to smoke n go back to sleep
@NickCannon: I'm reppin for all the goofy, corny, geeky kids! Just live your life like you want to! I made CORNY COOL!
@AsherRoth: Had a dream I was playing kickball against Esperanza Spalding. She had a 7 run inning. We scored 4...then I woke up...
@50Cent: Man I'm losing my damn mind these girls fine as hell and I don't remember them. Lol
@MattNathanson: i want u all to know i say f*ck way less on twitter than i do in real life. #lookwhosclassingupthejointnow
@remhq (R.E.M.): R.E.M. has collaborated with 15 other artists on "Download to Donate: Tsunami Relief" to provide relief for Japan: http://ow.ly/4kfob
@bobatl (B.o.B): I feel like a bad influence. Don't drink, don't drive, don't smoke, don't do any drugs, don't listen to secular music, or gamble. #TeamBoB
@MichelleBranch: may need to go find a patio somewhere that has fish tacos and ice cold margaritas. Don't make me do it, I will! #ConjuringSummer
@MarkHoppus: (Blink-182's Mark Hoppus) I saw something today that has shaken me to the core: skid marks in a urinal. Sadness. I can't trust the world anymore.
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READ LAST WEEK'S TWEETS