Actor Zac Efron has issued an apology after sharing a "completely insensitive" post on Martin Luther King Jr. Day on Twitter.

"I'm grateful for a couple things today: Martin Luther King Jr and 10 million followers on IG #MLKDay," Efron captioned an image of himself driving a convertible on sunset Monday.

But later, the actor deleted his original post and wrote: "I have nothing but the greatest admiration and respect for Dr. Martin Luther King Jr."

"I realise that last night's post was completely insensitive and I apologize to anyone who I may have offended. So sorry," he added in the post, reports aceshowbiz.com

His post angered some fans who accused Efron of being "offensive" and "savage" among others.

"@ZacEfron This is one of the most offensive/diminishing/disrespectful things anyone has said in relation to MLK today. Get over yourself," a fan wrote.