He did what on the red carpet?

Shocked ... US actor America Ferrera (second from left) reacts after the nasty incident surrounded by British actor Kit Harington (left), Australian actor Cate Blanchett (second from right) and Benin's actor Djimon Hounsou. Source: AFP

Watch as these celebrities lose their cool and accidentally say some inappropriate things on the red carpet and awards podiums.

CATE Blanchett was a shocked bystander as a man climbed under the dress of fellow actor America Ferrera on the Cannes red carpet.

The pair had arrived for the world premiere of How To Train Your Dragon 2 and were posing for a photo when the ugly incident occurred on Friday.

Festival security had to drag the man away after he rushed the red carpet wearing a suit and tie, jumped behind former Ugly Betty star Ferrera and slipped under her dress.

Ferrera was unhurt but clearly shaken up while Blanchett and Dragon co-stars Jay Baruchel, Kit Harington and Djimon Hounsou, all posing for the photo, were left shocked and shaking their heads.

A trespasser entered the red carpet of the Cannes Film Festival and dove quickly under actress America Ferrera's dress before security pulled him away. Courtesy: Fox 8 News/AP

Several reports claimed the man was Ukrainian journalist Vitalii Sediuk, a serial "prankster" at entertainment events.

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Sneaky ... the man under America Ferrera's dress at the How To Train Your Dragon 2 premiere. Source: Getty Images

Sediuk has in the past tried to kiss Will Smith on a red carpet, hugged the crotches of Leonardo DiCaprio and Bradley Cooper, and crashed the Grammys stage during Adele's acceptance speech.

The red carpet at the world's biggest film festival is renowned for its tight security.

What a drag ... the man is blocked by minders as he grabs US actor America Ferrera's ankle. Source: AFP

Officials are yet to comment on the incident.

Australian Naomi Watts also attended the premiere for the 3D animated film sequel, which has been well-received by critics at Cannes.

MORE PICTURES BELOW

Not a quiet exit ... the man is dragged away by minders after the embarrassing red carpet incident. Source: AFP

By her side ... Aussie actor Cate Blanchett comforts America Ferrera after the bizarre incident. Source: Getty Images

Off you go ... the man is led away by police officers after he tried to slip under US actor America Ferrera's dress. Source: AFP

No, seriously, you need to leave ... the man is taken away by a minder. Source: AFP