The duo release their latest album I Am Moron on April 3, and if you pre-order it at HMV Lancaster, you'll get a free wristband for a secret show in the city on April 5.
The show will be at an unannounced location (to be revealed the day before), somewhere in Lancaster City Centre.
Lead singer and guitarist Holly said: "The show will be absolutely free and will be an afternoon extravaganza to celebrate the launch of I am Moron and to thank all our hometown Lancaster fans for their support over the years.
"Tickets to the event are completely free.
"Early bird and guaranteed entry wristbands can be obtained by pre-ordering a copy of our album I am Moron on either CD or LP at HMV Lancaster.
"These wristbands will be available for collection along with the album when it arrives instore.
"If there are any remaining wristbands, they will be available from the event location on the day.
"The proceedings will kick off at 1.30pm. With the eggs performing a full live set at 4pm.
"This is going to be a fantastic afternoon session! Let's get on the lash with the Lancaster lot and celebrate our best album yet."
The band will also be performing a short stripped back in store performance in Lancaster HMV on at 5pm on Friday April 3.