Pop superstar Justin Bieber dedicated a song to his on/off girlfriend Selena Gomez during a surprise performance at the South by Southwest (Sxsw) festival in Austin, Texas.

The Baby hitmaker shocked fans when he showed up to sing As Long As You Love Me for the crowd at Banger's Sausage House & Beer Garden on Sunday (09Mar14).

Before launching into his performance, Bieber told the crowd, "This next song goes out to my baby". Gomez was reportedly in the audience following her concert in nearby Hidalgo on Saturday night (08Mar14).

The couple rekindled its romance in Texas on Friday (07Mar14) after Bieber flew to meet Gomez in Hidalgo after storming out of a deposition linked to a spat with a paparazzo on Thursday (07Mar14).

The lovebirds were spotted enjoying coffee at a local Starbucks and shopping at a nearby fragrance store. Reports suggest Bieber attended Gomez's concert on Saturday.