Zac Efron Apologizes for 'Completely Insensitive' Martin Luther King Jr. Post

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Zac Efron has issued an apology after sharing a "completely insensitive" post on Instagram.

The 28-year-old actor was slammed on social media for sharing a photo on Monday, aka Martin Luther King Jr. Day, with a caption reading: "I'm grateful for a couple things today: Martin Luther King Jr & 10 million followers on IG."

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Unsurprisingly, it took less than 24 hours for Efron to issue a mea culpa. The actor deleted his original post and wrote, "I have nothing but the greatest admiration and respect for Dr. Martin Luther King Jr. I realize that last night's post was completely insensitive and I apologize to anyone who I may have offended. So sorry."

Meanwhile, fans are demanding another apology from the star -- but they may be waiting much longer for this one.

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High School Musical fans were up in arms after Efron did not sit down for the franchise's 10th anniversary reunion special on Tuesday's Good Morning America, which included his former co-stars Vanessa Hudgens, Ashley Tisdale, Monique Coleman, Corbin Bleu and Lucas Grabeel.

Efron did record a message to share with fans during the telecast. "This is only 10 years -- let's have a billion more!" he said in the pre-recorded bit. "I love you guys!"

Sounds like Troy Bolton also has some explaining to do...