It may seem surprising the new dad follows the former Nickelodean star, but the two costarred together in She's the Man.
The twosome exchanged a series of heated tweets after McCarthy suggested Bynes "needs help." Luckily, the pair made up.
The former Hills star follows the 27-year-old actress on Twitter.
The Dancing With the Stars pro follows the aspiring singer on the social media site.
Mariah Carey's hubby reachout out to the troubled star—who he said was "like a sister"—in light of her recent behavior, although he's had no luck getting in touch.
The pint-size star called Bynes' behavior "entertaining" and has even suggested she needs her own reality show.
The fellow child star has spoken out about Amanda's antics, and she also follows her on Twitter.
The pop star and the actress crossed paths back in the day, and it looks like the Mother Monster is still a fan!
The former Victoria's Secret stunner keeps up with the 27-year-old on Twitter.
The New Girl star is apparently a fan of Amanda's quirky behavior.
"Am I the only one that is obsessed with her new makeover?" the new mom said of Amanda's makeover. Bynes even reciprocated her love on the social media site!
PHOTOS: Amanda Bynes' Sexy Selfie Twitpics