Justin Boober! Bieber goes a bit too (am)fAR as he grabs Heidi Klum's breast at gala in Cannes

They are no strangers after meeting up at showbiz events.

But Justin Bieber looked to made a bit of a boob during his latest meeting with Heidi Klum as he couldn't resist placing a cheeky hand on her breast while the pair posed for a picture together.

The 20-year-old singer was seen with his palm on the right side of the model's strapless midnight blue gown while they partied at the amfAR gala during the Cannes Film Festival on Thursday.

Keen: Justin Bieber made a boob at the amfAR gala at Cannes on Thursday night as he made a grab for Heidi Klum's breast

Hands-on: The 20-year-old singer was seen with his palm on the right side of the model's strapless midnight blue gown while they partied at the event at the Cannes on Thursday

The Never Say Never hitmaker clearly appeared to be enjoying the moment as he wore a broad smile across his face as he pulled off his handywork at the official afterparty, in association with Belvedere Vodka.

While Justin was all smiles, the expression on Heidi's face turned from a beaming grin to a slight smirk, if that.

But Heidi – who separated from singer Seal in 2012 - clearly only had eyes for one man on the night as she was seen enjoying a PDA fest with toy boy Vito Schnabel.

The only man for her: But Heidi - who separated from singer Seal in 2012 - clearly only had eyes for one man on the night as she was seen enjoying a PDA fest with toy boy Vito Schnabel

Greeting: Heidi looked delighted to see her toy boy while she sat at the table

Only eyes for one another: Heidi and Vito couldn't help but stare into each other's eyes

All smiles: The couple appeared to be having great fun at the event as they shared a laugh and a joke

The couple put on an extremely amorous display as they sat down at one of the tables at the event.

At that time Heidi was wearing a slinky pale blue number accented by silvery threading, and sexy details included a cleavage-exposing cut-out and leg-baring slit in the skirt, before later changing into the midnight blue number.

While Justin looked sharp in his classic black suit, he just couldn’t resist putting his expansive collection of body art on display.