Calvin Harris, Pharrell, Katy Perry and Big Sean are chasing this week’s Official UK Number 1

Plus songs from Dua Lipa, The Script, Charli XCX and Coldplay are climbing the Top 40.

Luis Fonsi, Daddy Yankee & Justin Bieber better watch their backs – another mega collaboration may topple them from the top spot this week.

Feels, Calvin Harris’ latest single featuring Pharrell, Katy Perry and Big Sean is gaining huge momentum, and comfortably sits in the Number 2 position on today’s sales flash.

While Despacito still has the lead on today’s Official Chart Update, Calvin and co are just 500 combined sales behind. Should Despacito slip from the top, Calvin will claim his eighth UK Number 1 single, Pharrell his fourth, Katy her fifth and Big Sean his first.

MORE: View Calvin Harris' full UK chart history

Racing up the chart from Number 12 to Number 3 midweek is Enrique Iglesias’ Subeme La Radio, featuring Sean Paul and X Factor winner Matt Terry, and the rest of the Top 5 also features high climbers. Rudimental and James Arthur occupy Number 4 at the midweek stage with Sun Comes Up, and Dua Lipa’s New Rules could reach new heights, up four to Number 5.

MORE: View this week's Top 100 Official Singles Chart Update in full 

New entries and high climbers

The Script are close to netting their fifth Top 10 entry at Number 10 with Rain (which has vaulted 21 places), while Jax Jones, Demi Lovato and Stefflon Don’s Instruction is also making huge gains, flying eight to Number 14.

Elsewhere, five other tracks could rise the ranks to crack the Top 40 for the first time. They are: Duke Dumont and Gorgon City’s Real Life (31); Charli XCX’s Boys (32); J Hus’ Spirit (34), Coldplay & Big Sean’s Miracles (36) and Arcade Fire’s Everything Now (37).

Finally, Camila Cabello’s OMG featuring Quavo could just squeeze into Friday’s Top 40, and is at Number 39 today.

View this week's Top 100 Official Singles Chart Update in full