Annacone will replace Lundgren with immediate effect
Peter Lundgren has resigned from his role as Great Britain's Davis Cup coach, with American Paul Annacone coming in as his replacement.
Annacone, the Lawn Tennis Association's men's head coach, will be in charge for September's World Group play-off.
"Peter is keen to spend more time with his father who is unwell - our thoughts are with him and his family," said GB Davis Cup captain John Lloyd.
"Peter has been a great asset but I am looking forward to working with Paul."
The first task for Annacone, former coach to Pete Sampras and Tim Henman, in his new role will be to prepare Great Britain for their play-off in September for the right to stay in the 16-team World Group.
"Paul has been working closely with many of our top players in his role as head coach and his knowledge and experience will be vital as we prepare for the World Group play-off," added Lloyd.
Britain will find out their opponents for the crucial match on 16 April.
Lundgren, who previously coached Roger Federer and Marat Safin, was been given a leave of absence by the LTA in June last year for "personal reasons".
The Swede was reported to have slurred his words when he spoke in front of fellow coaches at a conference at the LTA's headquarters.