Mother's Day 2015: Hollywood Stars Justin Bieber, Selena Gomez, Lucy Hale, Bella Thorne & More Honor Moms

Celebrities are so used to being in the limelight but the focus shifted to their mothers on Sunday, May 10. As the world celebrated the events, so many of these stars took to social media to shower their moms with greetings.

Leading the pack of stars honoring their moms on Mother's Day is Justin Bieber, whose message to his mom, Pattie, received over 1 million likes. Posting a photo of her on his Instagram account, the Canadian superstar thanked his mom for not giving up on him. His message read in part, "If it wasn't for this woman let's just say I would have had a way LONGER stupid phase." He credits his mom, all 4'9" of her, for teaching him everything he knows about staying strong.

Meanwhile, Selena Gomez celebrated with her father and the women in her family ahead of Mother's Day and posted a photo of the bunch on her Instagram as well. She captioned the photo, "Can't wait for my mom to get in town next week!" and then later posted a separate picture of her mother. In the pic, her mother was carrying her as she was planting a kiss on her cheeks. She simply captioned this, "Mommy."

Lucy Hale also posted a photo of her and her mom on Twitter and said, "Happy Mother's Day !! Celebrating how proud I am to be #JustLikeMyMother."

Bella Thorne shared an old family photo of her mom on Instagram and greeted her with a heart-warming message by thanking her for being both mom and dad to her, "Hopefully I can grow up to be half the woman you are," the young celebrity wrote.

Zac Efron also posted a photo of his mother on his Instagram and captioned this with "I love you with all my heart."

Rihanna's black and white photo of her mother was striking. She posted this on her Instagram and said, "Happy Motherz Day to the best, the sweetest, the illest, the "kill Ya wit a smile".... MAMA FENTZ!!!! Love you downe gurl!!! Mom, Thank you."

First Lady Michelle Obama also honored her mother in an Instagram post, saying that she's thankful for her love and support everyday. Obama also wished all the mothers a Happy Mother's Day.

Reese Witherspoon got to do several ways of honoring her mom on this special occasion which included hosting Saturday Night Live and enjoining the rest of the show's cast to apologize to their moms. She then posted several messages about Mother's Day on her Twitter account. She said she's lucky to have a "fun-loving, hysterical, down home mother" in Betty and that she's lucky to have her.