'He thinks it's me!' Jennifer Lopez is mortified as James Corden steals her phone to text Leonardo DiCaprio a flirty message during Carpool Karaoke

Jennifer Lopez learned a tough lesson...never give your phone to James Corden.

The 46-year-old pop star joined the late night host for his first ever primetime Carpool Karaoke session, set to air Tuesday night.

But Corden soon got a hold of J-Lo's phone and mischievously sent one of her contacts - none other than Leonardo DiCaprio - a message without the singer's permission.

Oh no! Jennifer Lopez learned a tough lesson...never give your phone to James Corden 

It began innocently enough with Corden asking her who was in her contacts list (Demi Lovato, Chris Brown, Bradley Cooper, Dwayne 'The Rock' Johnson, Iggy Azalea, and Fergie were just a few he discovered). 

'This is the best phone I have ever seen in my life!' he declared.  'Let me look at this. C'mon. This is insane!' 

'Can I please send one person a text in your phone?' he pleaded.

Impostor! Corden soon got a hold of J-Lo's phone and mischievously sent one of her contacts - none other than Leonardo DiCaprio - a message without the singer's permission

Let's get loud: Coden rapped about his Carpool Karaoke with J-Lo in a teaser ahead of the first Late Late Show Primetime Special on Monday

'Who?' J-Lo asked.

'Anyone!' Corden said boldly. 'Shall I text Leonardo DiCaprio?'

'No!' Lopez yelled. 

Corden then typed: 'Hey baby, I’m kind of feeling like I need to cut loose. Any suggestions? Let me know, J.Lo (you know from The Block)'. 

'You cannot send that!' J-Lo insisted but to no avail as Corden still went ahead and pressed send. 

They look good together: The funny man and the singer posed on a black SUV

Suddenly a smile: In this shot, Jenny From The Block looked more welcoming as Corden looked like a cat that got his cream

'Now I'm gonna have to explain this!' the dancer-turned-actress-turned-pop sensation said.

A few minutes later, J-Lo announced: 'He wrote back!'

She then read the text message from DiCaprio: 'You mean tonight, boo boo? Club wise?' 

'Here's the funny part,' J-Lo added, 'he thinks this is from me!' 

Meanwhile: Dicaprio was helping fight for sumateran elephant during his two day trip to the in Aceh, Indonesia, 26 March 2016. DiCaprio met and gave his support to local groups working to save this critical landscape from destruction by palm oil plantations, mining, logging, new roads and other development threats.

In the sneak peek for the upcoming Late Late Show special, Corden introduced his new series with a rap video revealing J-Lo all buckled up and ready to roll. 

'I went to my network boss and said "Screw it". Boss is like, "How 'bout a special? You wanna do it?" he raps to the tune of Macklemore & Ryan Lewis' Downtown in the minute-long clip. 'Primetime! Ten to eleven. Mainstream! Like a slice of heaven.'

He added: 'Viewers will watch it, critics will judge it, this part will make it way over budget,' he goes on as his crew burst through the Mona Lisa. 'Wasteful!'

The 37-year-old Brit's late night talk show usually airs at 12.37am, but CBS execs want to give earlier retiring audiences a taste of his hugely popular segment which sees him sing in his car with some of music's biggest names.  

Setting the scene: 'I went to my network boss and said "Screw it". Boss is like, "How 'bout a special? You wanna do it?" 

Big seller: The 37-year-old Brit's late night talk show usually airs at 12.37am, but CBS execs want to give earlier retiring audiences a taste of his hugely popular segment which sees him sing in his car with some of music's biggest names

'Viewers will watch it, critics will judge it, this part will make it way over budget,' he goes on as his crew burst through the Mona Lisa. 'Wasteful!'

'So tonight, I'm on my way before 12:30, cleaning up my language 'cause I can't talk dirty,' he continues. 

'I'll make your TV shine brighter than a halo, all leading up to a Carpool with J.Lo.'

'Tonight we'll give you something great,' he sings at the conclusion. 'You'll see what you've been missing late.' 

Rolling in the Jeep: by far his most popular invention is the crooning commute, which has seen the likes of Stevie Wonder, Adele, Sia, Mariah Carey, One Direction and Elton John go shotgun, while Justin Bieber has even come back for a second round

Occasion: The special marks his successful one year anniversary since he took over the slot from Scotland's Craig Ferguson

The special marks his successful one year anniversary since he took over the slot from Scotland's Craig Ferguson. 

He stirred up cookie cutter format of late night talk, opting against an MC and bringing across the Atlantic the concept of having all guests share the couch at the same time.

But by far his most popular invention is the crooning commute, which has seen the likes of Stevie Wonder, Adele, Sia, Mariah Carey, One Direction and Elton John go shotgun, while Justin Bieber has even come back for a second round.

New look: Corden stirred up cookie cutter format of late night talk, opting against an MC and bringing across the Atlantic the concept of having all guests share the couch at the same time

Best bits: The hour long special will relive some of the best moments so far, finishing with the brand new session with Jenny from the Block

'We call the carpool segments our gateway drug into James’ wacky world,' executive producer Rob Crabbe told NY Daily News.

'Getting a 10 o’clock special will give audiences a great taste of all the cool stuff that he’s doing after midnight.'

The hour long special will relive some of the best moments so far, finishing with the brand new session with Jenny from the Block. 

Busy: On Monday he 46-year-old was spotted filming the segment in WeHo

Leather as standard: The American Idol judge was well and truly buckled-up for the journey, with her towering thigh-high strappy bondage-inspired boots