She likes to keep us guessing with her outfit choices for the X Factor auditions.

And yesterday, Cheryl Cole went for a relatively simple look in a low-key khaki playsuit, which she teamed with black Christian Louboutin heels and a black cinch belt.

The singer, who turns 27 tomorrow, added extra glam with the help of some long gold earrings.

But then she knew she had to make an extra effort with Katy Perry as a guest judge on the panel.

Katy, predictably, opted for all-out glamour in a pale blue sequinned number.

The 25-year-old American is the latest in a string of guest judges adding a bit of oomph to proceedings in the absence of Dannii Minogue, who is on maternity leave.

Source | Pictures