Aston Villa winger Aleksander Tonev has joined Celtic on a season-long loan.
And the Scottish champions have an option to buy the 24-year-old Bulgarian international at the end of the arrangement.
"Aleksandar's a very quick player and he has two good feet which he can shoot with," said Celtic boss Ronny Deila.
"He scored a lot of goals at Lech Poznan and I think he can help bring the club forward with his qualities. We can also make him better."
Celtic were among the clubs strongly linked with Tonev before his £2.5m move to Villa was concluded in June 2013.
But he made just eight starts for Paul Lambert's side, with a further 12 appearances as a substitute.
"I can't wait to meet up with my new team-mates and start playing for Celtic," Tonev told the club website.
"I already knew all about Celtic. Everybody in Bulgaria knows Celtic. I spoke to Stiliyan Petrov yesterday and he was very happy for me. He wished me good luck and I hope I can do as well for Celtic as Stiliyan did.
"I'm an attacking player, and usually play on the left side of the park, and I like to create and score goals."
Capped 15 times, Tonev has three international goals but did not find the net during his season in England.