Side To Side Ariana Grande feat. Nicki Minaj
Lady Gaga's locked in a race with Justin Bieber for a new music industry record.
The pair are both heading for one billion YouTube views.
The experts reckon Gaga will win the race around October 20th as she's currently averaging 1.8 million views every day. Bieber will get to the billion mark around November 1st.
At the moment Bieber is the hotter of the two artists with around 3.7 million views every day. After Gaga and Bieber comes Michael Jackson.
So which are their videos are the most popular.
Gaga: Bad Romance (No 2 of all time), Just Dance, Alejandro and Telephone
Bieber: 'Baby' (YouTube's most watched video of all time); 'Never Let You Go' and 'Never Say Never'