LOS ANGELES • Daniel Radcliffe raps the alphabet. Mariah Carey sings karaoke to her own hits. Celebrities read out nasty tweets about themselves.
In the race to go viral, American late-night television hosts are bringing out the big guns.
Wedged between YouTube celebrities, Vine stars and an Internet full of cat videos, the hosts of late-night talk shows are putting a larger focus on becoming online sensations, creating meme-friendly content to draw an audience well beyond their tiny midnight viewership.
As entertainers compete for eyeballs in the cut-throat world of TV ratings, having a strong social media presence can help lure advertisers not just to broadcast TV, but also a broader range of online platforms.
Mr Seth Shapiro, digital media consultant and a governor at the Television Academy, bestowers of the Emmy awards, said: "It's the holy grail, to be able to sell cross- platform advertising."
NBC's The Tonight Show Starring Jimmy Fallon leads the social media race over eight late-night rivals - NBC's Late Night With Seth Meyers, ABC's Jimmy Kimmel Live, TBS' Conan, CBS' The Late Show With Stephen Colbert and The Late Late Show with James Corden, and Comedy Central's @midnight, The Daily Show With Trevor Noah and The Nightly Show With Larry Wilmore.
Fallon, whose Tonight Show team just won an Emmy for social media engagement, boasts 6.7 million Facebook fans, 8.3 million YouTube subscribers and nearly 30 million Twitter followers. Those numbers dwarf Fallon's regular TV audience, where he is also ratings leader with about 3.5 million nightly viewers.
Last month, 30 million people on Facebook engaged in content and discussion around the nine show hosts, with Fallon drawing 58 per cent of that chatter, Facebook said.
On Twitter, he garnered 963,000 mentions over a 30-day period, outpacing second-placed Kimmel's 242,000 mentions.
British entertainer Corden was little known in the United States before taking over The Late Late Show in March. It is his digital content that broadens his reach beyond his TV viewership of about 1.3 million, and also to international audiences, said executive producer Ben Winston. "It doesn't matter what your time slot is or what your lead-in is, the good content will survive," Mr Winston said.
Corden's most popular online clips are his Carpool Karaoke sketches, where he and his guests, such as Carey, sing along to their hit songs while he drives to work. Justin Bieber's appearance in May drew 35 million YouTube views.
Fallon and his Tonight Show team have "charted out a best practice for doing late night on social media", said Shapiro.
The comedian's penchant for parodies and musical numbers are viral bait. Harry Potter star Radcliffe rapping Blackalicious' Alphabet Aerobics has 48 million YouTube views. Other popular segments include Lip Sync Battles.
Kimmel has numerous online favourites including his faux feud with actor Matt Damon and his popular Mean Tweets, where celebrities read rude posts about themselves, drawing upwards of 50 million views.
Chris Hardwick's @midnight dominates Twitter trends well into the next day with #HashtagWars, as audiences tweet their answers to missives such as #MakeTV ShowsPunk or #SuperheroLyrics.
As a newcomer, Noah has a new digital team for The Daily Show to distribute content across numerous platforms. It is especially important for Noah, who garnered 29,000 tweets during his Monday debut, to connect with audiences on social media, executive producer Jen Flanz said.
She added: "He is young and he is engaged in that world. He is used to being a stand-up comedian and most of them have very open conversations with their fans almost all the time."
Social media also allows writers of late-night comedy to find new outlets for material often left out of the main show.
"On the old show (with Jon Stewart), we would have so much material that we would just throw it away," said Ms Flanz. "Now we have an endless amount of time and space and so we will use it."