In episode four, seven make-up artists remain - and they get their hands on some famous faces.

This week's guest judge is Caroline Barnes, a make-up artist to the stars who counts Cheryl, Gemma Chan, Emma Watson and Kylie Minogue among her clients. She's been working red carpets for over 20 years, so knows a thing or two about how to keep celebrity clients looking flawless and feeling good - something the MUAs need to emulate this week.