Holly Willoughby is to step down from co-hosting the talent show The Voice after two years, the BBC has announced.
The mother of two said she wanted to find the right balance between work and family life. She will be replaced by Big Brother presenter Emma Willis.
Meanwhile, Willoughby's co-host, Reggie Yates, also tweeted he would not be back for the BBC show's third series. His replacement will be announced soon.
The corporation thanked both hosts and wished them well for the future.
In a statement, Willoughby said: "After much consideration, I will not be returning for series three of The Voice UK."
"I've had two wonderful years on the show, and I feel very privileged to have been a part of it."
She went on: "Finding the right balance between my work and family life is my priority and this has contributed to my decision. I look forward to watching the next series from my sofa, and I wish the whole team the best of luck."
The ITV This Morning presenter has hosted the first two series of the BBC One singing contest with Yates, who said: "I've had a fantastic time on the last two series of The Voice UK and I wish all the team the best of luck for the new series."
The second series of The Voice suffered falling ratings, despite several format tweaks, designed to make the show more appealing.
Audiences dropped from an average 9.21 million in 2012, to 7.65 million in 2013 against competition from Britain's Got Talent on ITV.
However the final, in which Andrea Begley was crowned victor, outperformed the first series, with 7.95 million tuning in.
Willis, who has just finished a stint presenting Big Brother and also had presenting slots on This Morning - as well as hosting Heart FM's Sunday breakfast show - said: "The Voice is an absolutely brilliant TV show with the unique ability to showcase and nurture amazing raw talent.
"I couldn't be more excited to be a part of it and I cannot wait to get started."
The presenter, who is married to former Busted star Matt Willis, is not the only new recruit - pop star Kylie Minogue was announced as a replacement for Jessie J on the series earlier this week.
Mark Linsey, BBC controller of entertainment commissioning, said: "I'd like to thank Holly and Reggie for the fantastic job they've done on the first two series of The Voice UK but understand their reasons for leaving and wish them all the very best.
"With two new coaches on board and our two new presenters it's going to really mix things up."
The identities of Willis's co-host and the fourth judge have not been revealed. The next series will begin in January 2014.