[cnn-photo-caption image= http://i2.cdn.turner.com/cnn/2009/images/08/28/art.kennedy.obama.jpg caption="Obama will talk about the impact that the senator has had on him."]
(CNN) - A senior administration official tells that President Obama will describe Sen. Ted Kennedy as a "legislator, mentor and friend" in a 15-minute eulogy Saturday that will be a "personal message about the life of [the senator]."
Obama will talk about the impact that the senator has had on him, says the aide, but will not include a lot of stories about the relationship between the president and the man whose endorsement played a major role in his capture of the Democratic presidential nomination. Instead, it will be a broader message of a national goodbye and national tribute from the president. Obama will talk about Kennedy's legacy - his "impact on the American people" - but the exact language is not set - the president is still going over his remarks with a speechwriter
The first couple are expected to depart Martha's Vineyard for Boston, where Kennedy's funeral service will be held, around 9 pm Friday night.