Despite Bowie's death on January 10, Lennear is determined to finish the album the two started

Mick Jagger among her ex-boyfriends – it is said she inspired the Rolling Stone to write Brown Sugar

'He was the sweetest guy. It took every ounce of strength to continue on my journey to walk away from him,' says Lennear

Lennear won't say exactly why she split with Bowie, only that she 'stormed out' in a 'rage of anger'

'I would like to help you with your career, after this. Maybe we could get together and do a recording,' Lennear recalls Bowie telling her

She says Bowie tracked her down and he was writing music, while she was writing lyrics for new material

Superstar David Bowie was secretly working on new material before he died, a former girlfriend exclusively reveals to Daily Mail Online.

Claudia Lennear, who dated Bowie in the 1970s and was the inspiration for hit song Lady Grinning Soul, says the pair was collaborating on an album together.

In an exclusive interview with Daily Mail Online, Lennear says they had been working on the project for the past two years.

The album was supposed to be a comeback vehicle for Lennear, 68, a singer who turned her back on the music industry in the 1970s.

'We had this very strange writing relationship,' she says. 'He was writing music and I was writing lyrics.'

Lovers: Singer Claudia Lennear tells Daily Mail Online ex-boyfriend David Bowie tracked her down to start working on new material together. Bowie was working on the music, while Lennear was writing lyrics

No clue: Lennear, now a mother of two, says she had no indication Bowie was sick. 'He just looked like David getting older... And his voice was the David I always heard – that I always knew,' she recalls

Heartbroken: 'I may be able to temporarily get him out of my mind, by coping, but I'll never get him out of my heart,' Claudia says

But because the star was based in New York and Lennear lives in California, she says they mostly communicated via phone, email and FaceTime.

In fact, in one of his final texts to her, just days before his death on January 10, Lennear says the singer wrote: 'Send me some lyrics. Don't forget.'

Given that the 69-year-old had been battling terminal cancer for the past 18 months and had just completed his final album, Blackstar – working on yet more material would have been a remarkable feat for a dying man.

Yet the mother-of-two says she had no indication Bowie was sick, even though they used to chat via FaceTime regularly.

'He just looked like David getting older,' she says. 'He didn't look sick to me. And his voice was the David I always heard – that I always knew.'

It's a remarkable twist to a friendship that began more than 45 years ago.

A renowned backing vocalist who can count Mick Jagger among her ex-boyfriends – it is said she inspired the Rolling Stone to pen the hit Brown Sugar – Lennear was one of the singers featured in the Oscar-winning 2013 documentary 20 Feet From Stardom.

And it was through this film that she says she was able to reconnect with Bowie, whom she dated then dumped more than 40 years ago.

Lennear says she was in a car heading to the Independent Spirit Awards in Santa Monica, California in 2014 when her ex surprised her with a phone call, out of the blue.

'My cell phone went off and I didn't recognize the number. It was David who was telling me that he got my phone number from his business manager, who got the number from the film company.

'I was so delighted to hear from him.'

Emotional reunion: 'I had to scold him because, I said, 'David, I have tears in my eyes. You're making my mascara run,' Lennear tells of first conversation she and Bowie had more than 40 years after they broke up

Rumors?: Lennear says she knew nothing of the wild parties and orgies that Bowie allegedly engaged in at his London home with his wife Angie

Inspiration: Claudia was also romantically linked to Rolling Stone frontman Mick Jagger and is said to have inspired the band's hit Brown Sugar

Lennear, who had not seen or spoken to Bowie since they broke up, says the conversation quickly became emotional.

She says: 'I had to scold him because, I said, 'David, I have tears in my eyes. You're making my mascara run.'

It was during that conversation, Lennear says, that Bowie encouraged her to resume her singing career, which she abandoned following the poor response to her 1973 solo album Phew.

'I would like to help you with your career, after this,' she says he told her. 'Maybe we could get together and do a recording.'

Overcome with excitement, Lennear gushed about the chat when she got to the ceremony.

'Of course I couldn't wait to tell everybody,' she says. 'Oh my goodness. You'll never guess who I just heard from.'

'And so that became the talking point of that ceremony.'

When the film scooped the Independent Spirit Award for best documentary that night Lennear says Bowie reached out to her again.

She says: 'He sent me this beautiful text saying, 'Oh Claudia, what a wonderful way to end the day.'

'Just a sweet guy. I still can't believe he's gone.'

When Lennear met Bowie back in the early '70s she wasn't that impressed with the British singer.

They met at the Los Angeles home of entertainment attorney and agent Michael Lippman.

Sweet music: Lennear sang at a concert in December 2015, during which she shared the bill with Jackson Browne

Initially the seasoned R&B backing singer – who had worked with Ike and Tina Turner and had just finished the Mad Dogs and Englishmen Tour with Joe Cocker and Leon Russell – wasn't taken with Bowie.

'He was just so different from the singers and performers of my background,' Lennear says.

'I came from R&B so I was more in tune with people like Marvin Gaye or Al Green or even the Rolling Stones and The Beatles.'

She changed her tune when Bowie showed he was 'steeped in R&B' and they discovered they both liked soul singers like Carla Thomas and Dee Dee Sharp.

'Then I felt a little more comfortable talking about music,' Lennear says, 'because I had someone who understood and liked the same things.'

The pair exchanged phone numbers and quickly developed a friendship that blossomed into a romance.

'He was wonderful,' Lennear says. 'From my perspective I wasn't dating David Bowie. I was dating this guy that I liked.

'We did normal things. I would prepare dinner at my place and he would come by and just hang out.

'I had lots of musical instruments at my house in the Hollywood Hills.

'He would come and stay and hang out and play music and go through my record collection. We'd go to nightclubs together.'

Lennear says she knew Bowie was married, but she didn't mind. 'We had no such scruples in those days,' she says.

She would have cared, though, if she knew he was dating anyone else. Lennear says she knew nothing of the wild parties and orgies that Bowie allegedly engaged in at his London home with his wife Angie.

'If he did have other girlfriends it was kept from me,' she says, 'otherwise I probably would not have kept my door unlocked for him.

'I have a certain level of tolerance. If David was having wild times in London, I knew nothing of it.'

Bowie seemed to enjoy his time with Lennear. For years it was said that he wrote the 1973 song Lady Grinning Soul – an intimate ode to a lover – about her.

'He played that song over and over,' she says, 'but he never said anything then. Nor did I.

'Many of the lyrics were situations that we shared so I assumed he was writing this about Claudia.

Remembering Bowie: 'He will go down for me as probably one of the biggest regrets of my life. I don't think love ever goes away. Not if it's true,' Lennear tells Daily Mail Online

Personal collection: Lennear shows off her private David Bowie albums, which she says she has cherished all these years

'It wasn't until we reunited a couple of years ago, when we spoke on the phone, that he said, 'Oh Claudia, you are my Lady Grinning Soul.'

'So that's when it was confirmed for me.'

Lennear, who posed for Playboy at the height of her fame, looks back on these parts of her life with affection, without being in awe of Bowie, Jagger or the songs she supposedly inspired them to write.

'To me... it's Michael Philip and David Robert,' she says. 'That's just how I look at them both.

'Their public personas are totally different than my perspective of them.

'I don't look at them as these huge rock stars. I look at them as my boys. My babies.'

Lennear won't say exactly why she split with Bowie – only that she 'stormed out' in a 'rage of anger about a certain incident' she doesn't 'wish to disclose right now.'

She says: 'I can still see him standing there, not realizing that I had felt he was to blame and him trying to patch it up quickly before I started up my motor and drove off.

'He was the sweetest guy. It took every ounce of strength to continue on my journey to walk away from him.'

Not even her mother could convince her to change her mind. Around that time – the mid to late '70s – Lennear left Hollywood and moved back to her family home in Pomona, California.

Disillusioned with the music industry and her stalled solo career, she became a teacher to earn a regular wage to sustain her and her daughters.

But shortly after she returned her mother contacted Bowie and invited him to come to Pomona and have dinner with the family.

'She really liked him,' says Lennear who teaches to this day. 'Maybe somehow she, in her way, saw an opportunity to put us back together.

'I always felt very comfortable with him being around my family and my mother adored him.

'She was always the lightening gauge. 'This is a keeper,' she'd nudge me. 'She had a much better insight than I did.'

But Bowie and Lennear never rekindled their romance, even though she admits that she still loves him.

'He will go down for me as probably one of the biggest regrets of my life,' she says. 'I don't think love ever goes away. Not if it's true.

'David is the type of person – if you did find a way to love him – he is one who will always be in your heart.

'I may be able to temporarily get him out of my mind, by coping, but I'll never get him out of my heart.

'And he shouldn't be out of my heart. That's where he belongs.'

Special dedication: Claudia Lennear says she won't give up on the project and when she finishes it she will dedicate it to David

Making a comeback: Bowie wanted to help Lennear re-launch her career. Here she is with Judith Hill, Darlene Love and Tata Vega at the 22nd Annual Elton John AIDS Foundation Academy Awards in March 2014

Lennear believed Bowie still cared for her as a friend and this prompted him to bolster her efforts to re-launch her career.

She says he even suggested she turn to the fundraising site Kickstarter to get the project off the ground.

At the end of December she finally found someone who could help her do that.

'So that part of the team is all in place,' she says. 'But we have no David now.

'We had not put [the music and lyrics] together. I have enough for maybe two CDs in terms of lyrics.'

On both a professional and personal level Lennear says she is hurt that her old friend didn't confide in her that he was dying of cancer.

Of the album, she says: 'I had no idea that he was fighting a health timeline. If I had known I would have totally hustled to get things together.'

As for their friendship she says: 'It was the first time he didn't hold me in confidence. You can't believe the things we talked about over the years, or at least back in the day when we were close.

'I'm just heartbroken that he didn't share that with me so that maybe for once I could have given him some support.

'But, whatever his reasons were to not disclose this information, I'm sure they were worthy.'

For now her thoughts are with his family – his son Duncan Jones, his wife Iman and their 15-year-old daughter Alexandria.

She says: 'His wife and daughter I've never met, although I know who they are. David and I have had many conversations about them since we've reunited.

'I have an outpouring of, not only condolences, but great respect for them.'

Lennear is still reeling from the shocking late night text from a friend telling her Bowie had died.

She says her last correspondence with him was just 10 days earlier.

But she refuses to give up on the project they started. She is determined to finish the album.

She says: 'David is the type of person who – when he makes a commitment to do something – he sees it through from point A to point Z. He gets the project done.

'Back in the day, if he saw that I completed something it was always, 'Good girl.'

'I would look at him and say, 'David, you're making me seem like some trained animal.'

'And then we'd laugh, but that was just his affirmation.

'So that's why I think I'm going to go ahead and see this project through and just dedicate it to him.'

She added: 'He was one of the great blessings of my life. There never will be another David Bowie.