Lily Allen has shared with fans the news that she had an allergic reaction to the costume she sported to celebrate Halloween earlier this week.

The 28-year-old singer dressed up as an alien on October 31 to mark Halloween.

Allen’s Martian costume saw her sporting an all-green ensemble including a sequin dress, leopard print tights and a novelty headband.

She also painted her face and body green, which was the culprit of the ‘Smile’ vocalist’s adverse skin reaction.

Allen tweeted last night (Novemeber 2):

“'It's Saturday night and I've had a bad reaction to the green paint from Halloween, my face is covered in hives.”

However, it seems her pain was soothed by the sounds of a fellow Brit star as Lily informed her fans:

“Jessie J is on the radio, suddenly everything's fine.”

Lily Allen wore her extra-terrestrial costume to attend the UNICEF UK Halloween Ball in London where she performed with Robbie Williams. The event raised funds for UNICEF’s work for children affected by the crisis in Syria. 

Watch Lily Allen and Robbie Williams recording together below: