One Direction boys dominate top retweets list
Tweets from all four members of One Direction are among the top 10 most retweeted Twitter posts of 2015 - with Harry Styles at number one.
Departed member Zayn Malik is also on the list while Styles remains the most followed person in the UK with more than 26 million followers, according to the social media site's review of the year.
Tweets from Styles, Malik and Liam Payne make up the top three most retweeted posts, beating President Barack Obama into fourth place.
Styles' tweet, which has amassed more than 700,000 retweets, was posted in March and said: "All the love as always. H"
Malik, who left the boyband earlier this year saying he wanted to be a ''normal 22-year-old'', got more than 560,000 retweets on a tweet in August that said: "Proud of my boys the new single is sick. Big love. :) x"
Payne's July tweet, which has more than 490,000 retweets, said: "Wowwwww 5 years 5 boys what an amazing journey I couldn't thank you all ever enough and thank you Louis Niall Harry and zayn for everything"
Louis Tomlinson is at number five on the list with a tweet in July, that has more than 400,000 retweets, that said: "Our fans support really has been a different class ! Huge love to you guys !!"
And finally Niall Horan is at number seven with his August tweet - a picture of him with Payne retweeted more than 320,000 times - that said: "Happy birthday @Real_Liam_Payne .. Have a great day man .... Here we are making strange faces"
Meanwhile, Katy Perry continued her Twitter reign in 2015 as the most-followed individual, with over 78 million followers, and Rihanna broke into the global top five for the first time with more than 53 million followers.
Justin Bieber is at number two with 70.5 million followers, Taylor Swift is at three with 66.7 million and Barack Obama is at four with 66.5 million.
Styles leads the way in the UK with more than 26 million followers, Adele is close behind on more than 24 million, Payne is third with more than 21 million, Tomlinson is at four with almost 21 million, and Emma Watson is at five with 20 million.
Completing the top 10 most followed in the UK are Malik (16.6 million), Ed Sheeran (15.9 million), Simon Cowell (12.5 million), Wayne Rooney (12.2 million) and Stephen Fry (11.7 million).
Among the top trending television programmes in the UK were Celebrity Big Brother, Question Time, The X Factor, The Great British Bake Off, EastEnders Live, Eurovision Song Contest, Britain's Got Talent and Doctor Who.
The hashtag #MTVHottest was the top TV-related trend.
Among the top hashtags trending about music and entertainment were #VoteLittleMixUk, #OneDirection, and #BRITs2015.
Elsewhere, making it onto the list of the most memorable moments on Twitter was when Caitlyn Jenner joined.
In just over four hours, she amassed more than one million followers - breaking the record set by President Obama - to claim the title of fastest time to reach that mark.
Among other big names to join Twitter this year were Adrien Brody, Alan Shearer, Brooklyn Beckham, Chris Hemsworth and Diana Ross.
And Taylor Swift was one of many to tweet about the dress that went viral.
A photo of the same dress seen in different light captured the attention of millions of people who marvelled at the optical illusion or delved into the science behind the visual puzzle.
As people debated #BlueandBlack or #WhiteandGold, the dress sparked a global conversation in February, with more than 4.4 million Tweets.
Swift wrote: "I don't understand this odd dress debate and I feel like it's a trick somehow. I'm confused and scared. PS it's OBVIOUSLY BLUE AND BLACK"