Kevin Pietersen has succeeded Michael Vaughan as England cricket captain.
Following Vaughan's shock resignation on Sunday, the 28-year-old's appointment was confirmed by national selector Geoff Miller at Lord's.
Pietersen will captain both the Test and one-day sides and will lead England in the final Test against South Africa at The Oval on Thursday.
He said: "I'm very thrilled and excited to have been given the opportunity to captain England."
The South Africa-born batsman, who becomes England's 74th Test captain, had been widely tipped to take over from Vaughan and one-day captain Paul Collingwood, who also stood down on Sunday following England's Test series defeat to South Africa.
Kevin is a world-class player who will command the respect of the dressing room and I am sure he will be looking to lead from the front
England national selector Geoff Miller
Pietersen, who has played 42 Tests for England and burst onto the international stage in the famous Ashes win over Australia in 2005, added: "It's a huge honour and a terrific challenge for me at this stage of my international career.
"I have learned a great deal about leadership from playing under both Michael and Paul and fully appreciate the level of responsibility that comes with the job of captaining your country.
"My immediate priority will be this week's fourth npower Test and I will be devoting all my energies to ensuring that the team are properly prepared and play to their full potential, starting on Thursday."
Pietersen has captained England before, in the recent final one-day match against New Zealand, which England lost.
Miller, together with selectors Ashley Giles and James Whittaker and England coach Peter Moores, sat down on Sunday to decide on Vaughan's successor.
Other potential captains whose names were in the frame were Andrew Strauss, Alastair Cook and Kent skipper Rob Key.
Miller said: "In choosing a new captain, we were keen to identify a player who could lead the team in all three forms of cricket and bring fresh enthusiasm and ideas to the role of captain.
"Kevin is a world-class player who will command the respect of the dressing room and I am sure he will be looking to lead from the front and work closely with both the players and the coaching staff to bring England success in the future."
With Vaughan deciding not to play in the final Test, England have made one change to the squad with Essex's Ravi Bopara replacing him.
England also announced the squad for five one-day internationals with all-rounder Andrew Flintoff returning in place of Hampshire's Dimitri Mascarenhas.
We need to unite and get onto the same hymn sheet
Pietersen on his relationship with Peter Moores
Sussex wicketkeeper-batsman Matt Prior has earned a recall as a replacement for Tim Ambrose while uncapped Nottinghamshire all-rounder Samit Patel is included for the first time.
Pietersen started his tenure as England captain praising his predecessor Vaughan.
"What a great man he was as a skipper - They are huge boots to fill and I'll try to give it the best possible go I can," said the new captain.
"He was a great leader, he brought me into the side and I always tried to the best I could for a great man."
Pietersen said he would look to the senior players for advice but wanted to stamp his own captaincy style on the national team and he did not believe his own form would suffer because of the extra burden.
"I will always respect what has happened in the past and I will always respect what Michael did and what my predecessors did," he said.
"I will always look for advice because I'm new in this job and I've had calls and messages from the senior players in the squad.
From what I'm hearing (Kent captain) Rob Key was in second place
BBC cricket correspondent Jonathan Agnew
"Once you have the support of the lads around you, you can't ask for any more.
"But I'll have my own ways and it's very exciting. It's a brand new test and a bright new challenge for me."
There have been suggestions Pietersen has had a strained relationship with coach Moores but he insisted they would have no trouble working as a team.
"I don't think I would be sitting here today if I wasn't 100% confident that everything is going to be perfectly fine," said Pietersen.
"Yesterday I sat down with Peter and we had a really good discussion on how we want to take this team forward.
"My position as a player to becoming captain is now totally different and we need to unite and get onto the same hymn sheet and we need to get this team going forward."
BBC cricket correspondent Jonathan Agnew said that once the selectors had decided to appoint one captain for all forms of the international game, Pietersen was the logical choice.
"He was the only real candidate once the selectors decided there was only going to be one captain - that was the big decision," said Agnew.
"From what I'm hearing (Kent captain) Rob Key was in second place, if you like. I'm not saying it was a close contest between Pietersen and Key at all, I don't think it was.
"But because they wanted that starting point of a unified captain, Key was higher up the pecking order, I think, even than Andrew Strauss."
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