Rebecca Black's fifteen minutes just keeps getting extended ... thanks to superstars like Katy Perry.

During Perry's weekend concert in LA, the "Friday" singer got to join the "California Gurl" songstress on stage. From the looks of it, Katy really loves Rebecca.

The 14-year-old web sensation also scored a surfboard trophy at the 2011 Teen Choice Awards for Choice Web Star. Talk about a great weekend!

See Rebecca's latest music video ... after the jump.