The 32-year-old Tongan international joins from Plymouth Albion and can play centre, full-back or scrum-half.
Tu'ipulotu played in the 1999 and 2007 World Cups and made 65 appearances for Newport Gwent Dragons between 2003 and 2006.
"Sione has been one of the key performers for Plymouth Albion in the last two seasons," said Warriors head coach Richard Hill.
"He's a very powerful centre and in the Premiership you need that type of player because defences are so well drilled and strong.
"He has good footwork while having the same kind of destructive power as the likes of Aleki Lutui and Dale Rasmussen."
Gilbert has released a new line of rugby cleats. The Gilbert Virtuo 8S is part of the exciting new product. Check it out.
The entire All Blacks apparel line has been updated for 2013/14. Check out the New Zealand All Blacks polo.
The Nike Tiempo is a solid rugby cleat and one of few styles still made from full-grain natural leather.
The Gilbert Blitz 8S rugby cleat is a great cleat at a great price of $69.99. Get a new pair of cleats today.
A cool looking all black rugby cleat with the high performance adidas is known for. Get in the Gear!
Wear the crest of the British and Irish Lions on your t-shirt. A great look for the summer.
The All Blacks Performance t-shirt is black with hints of blue from the training jersey. Very Cool.
The New Zealand All Blacks training jersey for 2013/14. Get in the Gear!
The USA Rugby Pro Alternate rugby jersey is perfect for any fan of the Eagles. Get yours to wear during the summer Test matches.
The NEW All Blacks 2013/14 jersey has arrived at World Rugby Shop. Dare to wear the colors of the All Blacks.