It's Selena, the human shield! Justin Bieber thrusts girlfriend Gomez into the spotlight as he hides behind her in London

It might seem chivalrous to let the lady go first.

But Justin Bieber seems to be using Selena Gomez as a human shield.

The lovebirds were seen leaving Kiss FM radio station in London, with the Baby singer rumoured to be on UK shores for an appearance on X Factor.

Instead of basking in the glory of the spotlight, 17-year-old Bieber took a backseat and let his girlfriend lead the way.

Bieber gave little indication as to why he is in the capital, simply writing on Twitter: 'great time in Madrid. now back to London. Leggo'

It is thought the Canadian pop prince will be a surprise guest on the ITV results show tomorrow night alongside already announced acts Lady Gaga and One Direction, or he is prerecording his performance for next week.

Bieber also acted strangely as he left the Radio 1 studios earlier in the day, leaving the building and heading to the car with what appeared to be a cereal bowl covering his face.As the couple, who have been dating since March, landed at Heathrow, again Bieber kept his head buried from photographers and fans.

Walking through the airport, he kept his head hidden beneath a black hoodie and held onto the edge so it didn't fall back onto his shoulders.

The young Brit Award-winner is currently at the centre of a paternity accusation, with Mariah Yeater claiming he is the father of her child.

Yeater, 20, allegedly met Bieber in October 2010 after a gig at the Staples Centre arena in Los Angeles.

The pair reportedly had a sexual liasion, which Yeater claims resulted in the birth of her son Tristyn.