Dejan Stankovic is married to Milenko's sister Anna and, apart from the family ties, the pair are good friends and were team-mates briefly at Red Star Belgrade in 1998.
That's when Yugoslav international Stankovic moved to Italy but the pair stay in regular contact and their families went on holiday together this year.
Slovenian star Milenko revealed: "I played with Dejan at Red Star and he is married to my sister. They have two boys. We are family and this will be the first time I play against him.
"We are normally together all the time, holidays, but this time we are not friends for 90 minutes!
"He is an excellent player. He had problems in his first year at Lazio but now he plays well and for me, he is one of the best players at Lazio.
"We speak every day on the telephone and we are good friends. He is a very nice man and a very good player. It will be a special day."
In fact, it will be another special day for Milenko after his debut at the Lane in Wednesday's draw against Celtic. The 22,000-plus crowd were treated to a few tricks and turns and he went off to a standing ovation.
Milenko beamed: "It was my first game at White Hart Lane and I will never forget it. It was a friendly but there were many people in the stadium and everything went well. It was something special."
Sunday's cracker against Lazio will be that little extra special for Milenko Acimovic - he'll be up against his brother-in-law for the first time.