New Portsmouth co-owner Alexandre Gaydamak says his first ambition at Fratton Park is to help the club stay in the Premiership.
The 29-year-old Russian businessman was unveiled as partner to Pompey chairman Milan Mandaric at a news conference.
Gaydamak said: "I'm thrilled and happy to be one of the co-owners, I'm looking forward to a great future at this club.
"At the moment we must try and stay in the Premiership. After this season we will then talk about the next step."
Gaydamak will have a 50% stake in the Fratton Park club and will be an equal partner with Mandaric.
Mandaric hailed the dawn of a new era for Portsmouth and said he thought Gaydamak could take the club on to the next level.
"It is an exciting and important day for our football club - there is now two of us instead of one," said Mandaric.
"Alex is a tremendous young man with great enthusiasm for football and Portsmouth and it's a great pleasure to have him on board.
"Sport is a business, unless you have silly money to throw at it, and we will continue to treat it in such a way.
"My mission here was to take the club into the Premiership, establish it there and re-build the stadium - I believe he can help me complete my mission.
"It's not easy to find good investors. We are extremely lucky to have such a young, enthusiastic guy at our club."
Gaydamak's father Arcadi is the subject of an international arrest warrant in relation to his alleged part in an oil-for-arms deal to Angola in 1994, although he denies any wrongdoing.
But Alexandre moved to reassure Pompey fans that his investment was purely a solo project.
"I believe I'll pass any tests by the Premier League over my suitability," he added. "I'm doing my own business.
"There's no relationship between my father and Portsmouth. I don't need his money to do my own business.
"It's my money, money I've made from 10 years of working. I was working in finance and real estate in Russia, that's my work."
Portsmouth also unveiled new record £4.1m signing Benjani Mwaruwari but Gaydamak refused to say how much money boss Harry Redknapp would be given to spend.
"I met Harry on Thursday and had a pleasant conversation but everything we do will be decided by the whole management," said Gaydamak.
"We are discussing the transfer policy with the management. You will see results in time."