Free pairs of underwear are on offer to young people in Northamptonshire who get themselves screened for Chlamydia.
Northamptonshire Healthcare NHS Foundation Trust is giving away the briefs - which contain an anti-STI message - with their free home-screening postal kits.
The offer is being made to people aged 15-24 in the run up to Valentines Day.
Jason May from Northamptonshire Healthcare NHS Foundation Trust said: “With Valentine’s Day just around the corner, we want to remind people of the need to practice safe sex, and get themselves checked out.
"Chlamydia is the most common sexually transmitted infection in the country and because it often has no symptoms, many people don’t know they have it."
For a free Chlamydia testing kit, call 0845 602 311 or email firstname.lastname@example.org