Will Smith has joined Instagram - with a grand welcome from celebrity pal Justin Timberlake.

The 'Suicide Squad' star announced his arrival on the photo sharing social media site on 'The Ellen Degeneres Show' where the chat show host showed him the ropes, persuading him to dress up as his breakthrough alter ego The Fresh Prince for his very first Throwback Thursday (#TBT) shot.

Justin Timberlake was quick to welcome 49-year-old Will to Instagram with a Throwback Thursday shot of the pair together.

Justin wrote: ''Welcome to Instagram @willsmith. This is called a #TBT. Which means Throwback Thursday. Which is a photo you post on Thursdays that you like, that was taken in the past. I like this photo because it's a photo of you and me. And we look like we are having a serious conversation about something very important. And that makes me feel important.''

And his wife Jada Pinkett Smith posted: ''Welcome to Instagram @willsmith :)''

Chat show host and avid social media user Ellen posed for a selfie with Will and also joked with him about using Instagram t post pictures of food and babies.

She sent a message to the 'Fresh Prince of Bel-Air' star saying: ''Welcome to Instagram, @WillSmith! Glad I could help. #Repost @WillSmith''

Will has since shared an adorable picture of himself as a baby, writing: ''Ya'll ain't got no filters like this (sic)''

In less than 24 hours Will has racked up over 900,000 followers.

Will's teenage children Jaden Smith, 19, and Willow Smith, 17, are yet to welcome their dad to the social media network.