Those Harry Potter stars gotta stick together!
"He looks very serious here but is hilarious in #Bluestone42. Watch @Mattdavelewis on @BBCthree Monday@10pm. So Good!!"
Lewis returned the compliment by writing, "Always said you're my favourite!" back to her on Twitter.
And when she isn't busy supporting her fellow actor friends, Watson has been hard at work as an advocate of the HeForShe campaign and a U.N. Women Goodwill Ambassador.
She recently sat down for an interview on her Facebook page in honor of International Women's Day, where she answered a slew of questions from fans on a variety of topics.
At one particularly moving point in the chat, Watson was asked about how one should handle gender inequality in the workplace.
"Argh, just don't let anyone tell you what you can and cannot do or can and cannot achieve," she explained to the fan.
"Just don't allow it. Just do not allow it. It's wrong. It's so wrong. Be whatever you want to be."