Bayer Leverkusen, in pursuit of a treble, are rewarding its fans with complimentary club tattoos to honor their Bundesliga triumph and remarkable unbeaten streak, the champions announced on Friday.

Under the guidance of Xabi Alonso, the team has maintained an unblemished record throughout all competitions this season, culminating in a thrilling 2-2 comeback against AS Roma on Thursday, securing their place in the Europa League final with a 4-2 aggregate victory.

They stretched their unbeaten run this season to 49 matches across all competitions, surpassing Benfica's long-standing European record set from 1963 to 1965.

"A special action at the end of a special season. Bayer 04 is offering fans ... until the end of the season the opportunity to choose one of the many Bayer 04 tattoos for free," the club said in a statement.

"Book your appointment now to eternalize this unique season on your skin."

After sealing their first-ever Bundesliga title, Leverkusen are also through to the German Cup final, where they will face Kaiserslautern in what could be a treble-winning season for the club.