Houllier has ended his nine-month reign with immediate effect after suffering heart problems which meant he could not take charge of the team for the final five games of the season. He showed his faith in Bent by splashing out an initial ?£18 million to Sunderland in January and he responded with nine goals in 16 games.
Bent said: "It is sad for me to see Gerard go. He signed me, invested a lot of money in me. He showed a lot of faith in me."
He added: "But your health comes first and, if he's not well enough to come back, then he needs to take a break."
It has been common knowledge for 24 hours that Houllier's reign was coming to an end after he underwent further medical tests before the weekend.
Villa will now step up their search to find a replacement with Fulham's Mark Hughes one of the early names to be linked with the post.
Doctors have advised that Houllier will require further time to recuperate although the 63-year-old is not ruling out an eventual return to the game.
Villa chief executive Paul Faulkner said: "We regret the circumstances of Gerard's departure and, naturally, we wish him well in his continued recovery.
"I know I speak for everyone associated with Aston Villa in expressing our hope that Gerard will return to full health as quickly as possible and we wish him all the best for the future."
Faulkner added: "As a board we are very conscious of the need to ensure that the club is prepared fully to meet the demands of the new season. To that end, we have already embarked upon the process which will lead to the appointment of a new manager."
Source: PA
Source: PA