Southampton completed the signing of striker Adam Armstrong from Blackburn on a four-year deal for a reported £15 million on Tuesday.
Armstrong's arrival helps fill the void left by the departure of last season's top goalscorer Danny Ings to Aston Villa earlier this month.
"It's unbelievable to be here - such a massive club with a great fanbase and it's just something that I'm really looking forward to," said the 24-year-old, who scored 28 goals in the Championship last season.
"I thought it was perfect as my next step. I wanted to get back to the Premier League from what I've done for Blackburn, so I'm over the moon."
Saints also announced the signing of Chelsea attacker Armando Broja on a season-long loan on Tuesday.
The 19-year-old signed a five-year contract with the European champions in July after impressing on loan at Vitesse Arnhem last season.
"Armando is a very talented player who we were impressed by last season," said Southampton manager Ralph Hasenhuttl.
"He is young, but he comes now with a full season of experience in senior football with a good team, and he brings a lot of qualities that can help us."
Southampton begin their Premier League campaign away to Everton on Saturday.