The 20-year-old joined Celtic on a season-long loan last season and during the summer signed permanently at Parkhead.
"It allows us more options with the systems we play".
Weah, the son of legend George Weah, has largely been deployed as a wide player with both PSG and the USA national team but, under Brendan Rodgers, the forward is expecting to be played centrally.
'I am in love with Celtic so I am really happy, ' he told BBC Scotland.
Celtic fans will now be hoping that the club continues its transfer business by strengthening the defensive side of the team as the Scottish champions look to secure their eighth title in a row and the possibility of an historic treble-treble. I'm so excited to be here.
Weah, the son of former AS Monaco and AC Milan player and current Liberia president George, has scored twice in six games for PSG and netted once in eight internationals. "It was a great feeling getting to know a new team and new coaching staff".
"A few years later, I am playing alongside Neymar and [Kylian] Mbappe. We're still top and have a game in hand, so it's going the right way".
"It is really hard to impose yourself with such great players in front of you".
This morning the player posted an image of himself training in Dubai with Celtic, and his excitement shines through in the tag line.
The eight-times capped United States global signed on Monday for the rest of the season and joined his new team-mates at their training camp in Dubai. "He's hungry too", Celtic boss Brendan Rodgers told the club's website.
Weah said he "received "a lot of offers" to go on loan this winter, but Celtic was the one that stood out for him".
He said: "The manager has said he wants to add new players and seeing new players coming into the squad is a good thing for everyone at the club and the supporters".